Merge branch 'docs-feature-flag-distrib' into 'master'

Move feature flag page to Distribution

See merge request gitlab-org/gitlab!71656

doc/administration/feature_flags.md

 ---
-stage: none
-group: Development
-info: "See the Technical Writers assigned to Development Guidelines: https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments-to-development-guidelines"
-type: reference
+stage: Enablement
+group: Distribution
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
 description: "GitLab administrator: enable and disable GitLab features deployed behind feature flags"
 ---