Add reduce container registry page and update links

app/views/admin/application_settings/_registry.html.haml

@@ -10,10 +10,10 @@
         = f.check_box :container_expiration_policies_enable_historic_entries, class: 'form-check-input'
         = f.label :container_expiration_policies_enable_historic_entries, class: 'form-check-label' do
           = _("Enable container expiration and retention policies for projects created earlier than GitLab 12.7.")
-          = link_to sprite_icon('question-o'), help_page_path('user/packages/container_registry/index', anchor: 'cleanup-policy')
+          = link_to sprite_icon('question-o'), help_page_path('user/packages/container_registry/reduce_container_registry_storage', anchor: 'cleanup-policy')
         .form-text.text-muted
           = _("Existing projects will be able to use expiration policies. Avoid enabling this if an external Container Registry is being used, as there is a performance risk if many images exist on one project.")
-          = link_to sprite_icon('question-o'), help_page_path('user/packages/container_registry/index', anchor: 'use-with-external-container-registries')
+          = link_to sprite_icon('question-o'), help_page_path('user/packages/container_registry/reduce_container_registry_storage', anchor: 'use-with-external-container-registries')
     - if container_registry_expiration_policies_throttling?
       .form-group
         = f.label :container_registry_delete_tags_service_timeout, _('Cleanup policy maximum processing time (seconds)'), class: 'label-bold'

app/views/projects/registry/repositories/index.html.haml

@@ -12,7 +12,7 @@
     "containers_error_image" => image_path('illustrations/docker-error-state.svg'),
     "repository_url" => escape_once(@project.container_registry_url),
     "registry_host_url_with_port" => escape_once(registry_config.host_port),
-    "expiration_policy_help_page_path" => help_page_path('user/packages/container_registry/index.md', anchor: 'cleanup-policy'),
+    "expiration_policy_help_page_path" => help_page_path('user/packages/container_registry/reduce_container_registry_storage', anchor: 'cleanup-policy'),
     "garbage_collection_help_page_path" => help_page_path('administration/packages/container_registry', anchor: 'container-registry-garbage-collection'),
     "run_cleanup_policies_help_page_path" => help_page_path('administration/packages/container_registry', anchor: 'run-the-cleanup-policy-now'),
     "project_path": @project.full_path,

app/views/projects/settings/packages_and_registries/show.html.haml

@@ -10,6 +10,6 @@
     is_admin: current_user&.admin.to_s,
     admin_settings_path: ci_cd_admin_application_settings_path(anchor: 'js-registry-settings'),
     enable_historic_entries: container_expiration_policies_historic_entry_enabled?(@project).to_s,
-    help_page_path: help_page_path('user/packages/container_registry/index', anchor: 'cleanup-policy'),
+    help_page_path: help_page_path('user/packages/container_registry/reduce_container_registry_storage', anchor: 'cleanup-policy'),
     show_cleanup_policy_on_alert: show_cleanup_policy_on_alert(@project).to_s,
-    tags_regex_help_page_path: help_page_path('user/packages/container_registry/index', anchor: 'regex-pattern-examples') } }
+    tags_regex_help_page_path: help_page_path('user/packages/container_registry/reduce_container_registry_storage', anchor: 'regex-pattern-examples') } }

doc/administration/packages/container_registry.md

@@ -694,7 +694,7 @@ project, you can [disable it from your project's settings](../../user/project/se
 ## Use an external container registry with GitLab as an auth endpoint
 
 If you use an external container registry, some features associated with the
-container registry may be unavailable or have [inherent risks](../../user/packages/container_registry/index.md#use-with-external-container-registries).
+container registry may be unavailable or have [inherent risks](../../user/packages/container_registry/reduce_container_registry_storage.md#use-with-external-container-registries).
 
 For the integration to work, the external registry must be configured to
 use a JSON Web Token to authenticate with GitLab. The
@@ -883,7 +883,7 @@ project.container_repositories.find_each do |repo|
 end
 ```
 
-You can also [run cleanup on a schedule](../../user/packages/container_registry/index.md#cleanup-policy).
+You can also [run cleanup on a schedule](../../user/packages/container_registry/reduce_container_registry_storage.md#cleanup-policy).
 
 ## Container Registry garbage collection
 

doc/administration/troubleshooting/gitlab_rails_cheat_sheet.md

@@ -1272,8 +1272,8 @@ registry.replicator.send(:sync_repository)
 
 ## Generate Service Ping
 
-The [Service Ping Guide](../../development/service_ping/index.md) in our developer documentation 
-has more information about Service Ping. 
+The [Service Ping Guide](../../development/service_ping/index.md) in our developer documentation
+has more information about Service Ping.
 
 ### Generate or get the cached Service Ping
 
@@ -1299,7 +1299,7 @@ rake gitlab:usage_data:generate
 
 Generates Service Ping data in YAML format:
 
-```shell 
+```shell
 rake gitlab:usage_data:dump_sql_in_yaml
 ```
 

doc/api/container_registry.md

@@ -395,7 +395,7 @@ The number of tags deleted by this API is limited on GitLab.com
 because of the scale of the Container Registry there.
 If your Container Registry has a large number of tags to delete,
 only some of them will be deleted, and you might need to call this API multiple times.
-To schedule tags for automatic deletion, use a [cleanup policy](../user/packages/container_registry/index.md#cleanup-policy) instead.
+To schedule tags for automatic deletion, use a [cleanup policy](../user/packages/container_registry/reduce_container_registry_storage.md#cleanup-policy) instead.
 
 NOTE:
 In GitLab 12.4 and later, individual tags are deleted.

doc/architecture/blueprints/container_registry_metadata_database/index.md

@@ -78,7 +78,7 @@ The single entrypoint for the registry is the [HTTP API](https://gitlab.com/gitl
 | Operation                                                    | UI                 | Background               | Observations                                                 |
 | ------------------------------------------------------------ | ------------------ | ------------------------ | ------------------------------------------------------------ |
 | [Check API version](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#api-version-check) | **{check-circle}** Yes | **{check-circle}** Yes | Used globally to ensure that the registry supports the Docker Distribution V2 API, as well as for identifying whether GitLab Rails is talking to the GitLab Container Registry or a third-party one (used to toggle features only available in the former). |
-| [List repository tags](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#listing-image-tags) | **{check-circle}** Yes | **{check-circle}** Yes | Used to list and show tags in the UI. Used to list tags in the background for [cleanup policies](../../../user/packages/container_registry/#cleanup-policy) and [Geo replication](../../../administration/geo/replication/docker_registry.md). |
+| [List repository tags](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#listing-image-tags) | **{check-circle}** Yes | **{check-circle}** Yes | Used to list and show tags in the UI. Used to list tags in the background for [cleanup policies](../../../user/packages/container_registry/reduce_container_registry_storage.md#cleanup-policy) and [Geo replication](../../../administration/geo/replication/docker_registry.md). |
 | [Check if manifest exists](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#existing-manifests) | **{check-circle}** Yes | **{dotted-circle}** No | Used to get the digest of a manifest by tag. This is then used to pull the manifest and show the tag details in the UI. |
 | [Pull manifest](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#pulling-an-image-manifest) | **{check-circle}** Yes | **{dotted-circle}** No | Used to show the image size and the manifest digest in the tag details UI. |
 | [Pull blob](https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/spec/api.md#pulling-a-layer) | **{check-circle}** Yes | **{dotted-circle}** No | Used to show the configuration digest and the creation date in the tag details UI. |

doc/user/admin_area/settings/index.md

@@ -64,7 +64,7 @@ The **CI/CD** settings contain:
   This pipeline configuration is run after the project's own configuration.
 - [Package Registry](continuous_integration.md#package-registry-configuration) -
   Settings related to the use and experience of using the GitLab Package Registry. Some
-  [risks are involved](../../packages/container_registry/index.md#use-with-external-container-registries)
+  [risks are involved](../../packages/container_registry/reduce_container_registry_storage.md#use-with-external-container-registries)
   in enabling some of these settings.
 
 ### Geo **(PREMIUM SELF)**