Add hashed storage checks to `gitlab:app:check`

Backported hashed storage checks to CE and updated documentation to
state that Hashed Storage deprecated in 13.0

changelogs/unreleased/213556-move-the-hashed-storage-checks-to-gitlab-app-check-task-instead-of.yml

+---
+title: app:gitlab:check rake task now warns when projects are not in hashed storage
+merge_request: 31172
+author:
+type: changed

ee/lib/system_check/app/hashed_storage_all_projects_check.rb → lib/system_check/app/hashed_storage_all_projects_check.rb

@@ -11,8 +11,8 @@ module SystemCheck
 
       def show_error
         try_fixing_it(
-          "Please migrate all projects to hashed storage#{' on the primary' if Gitlab::Geo.secondary?}",
-          "to avoid security issues and ensure data integrity."
+          "Please migrate all projects to hashed storage#{' on the primary' if Gitlab.ee? && Gitlab::Geo.secondary?}",
+          "as legacy storage is deprecated in 13.0 and support will be removed in 13.4."
         )
 
         for_more_information('doc/administration/repository_storage_types.md')

lib/system_check/rake_task/app_task.rb

@@ -31,7 +31,9 @@ module SystemCheck
           SystemCheck::App::GitVersionCheck,
           SystemCheck::App::GitUserDefaultSSHConfigCheck,
           SystemCheck::App::ActiveUsersCheck,
-          SystemCheck::App::AuthorizedKeysPermissionCheck
+          SystemCheck::App::AuthorizedKeysPermissionCheck,
+          SystemCheck::App::HashedStorageEnabledCheck,
+          SystemCheck::App::HashedStorageAllProjectsCheck
         ]
       end
     end