Remove feature flags

This removes a feature flags
that are referenced by `feature_available?`

config/feature_flags/development/builds.yml

----
-name: builds
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: 
-default_enabled: true

config/feature_flags/development/forking.yml

----
-name: forking
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: group::source code
-default_enabled: true

config/feature_flags/development/issues.yml

----
-name: issues
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: 
-default_enabled: true

config/feature_flags/development/merge_requests.yml

----
-name: merge_requests
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: group::code review
-default_enabled: true

config/feature_flags/development/metrics_dashboard.yml

----
-name: metrics_dashboard
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/29634
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/257902
-milestone: '13.0'
-type: development
-group: group::monitor
-default_enabled: true

config/feature_flags/development/operations.yml

----
-name: operations
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/48347
-rollout_issue_url:
-milestone: '13.7'
-type: development
-group: group::editor
-default_enabled: true

config/feature_flags/development/pages.yml

----
-name: pages
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: 
-default_enabled: true

config/feature_flags/development/repository.yml

----
-name: repository
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: group::source code
-default_enabled: true

config/feature_flags/development/snippets.yml

----
-name: snippets
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: 
-default_enabled: true

config/feature_flags/development/wiki.yml

----
-name: wiki
-introduced_by_url: 
-rollout_issue_url: 
-milestone: 
-type: development
-group: group::editor
-default_enabled: true