Propose ownership metadata for API pages

Use introduced-in lines and cues from page contents to suggest
stage and group ownership for some API docs pages.

doc/api/appearance.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Access
 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/#designated-technical-writers
 ---
 

doc/api/dependency_proxy.md

 ---
-stage: none
-group: unassigned
+stage: Package
+group: Package
 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/#designated-technical-writers
 ---
 

doc/api/epic_links.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Product Planning
 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/#designated-technical-writers
 ---
 

doc/api/geo_nodes.md

 ---
-stage: none
-group: unassigned
+stage: Enablement
+group: Geo
 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/#designated-technical-writers
 ---
 

doc/api/group_activity_analytics.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Optimize
 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/#designated-technical-writers
 ---
 

doc/api/group_import_export.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Import
 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/#designated-technical-writers
 ---
 

doc/api/notes.md

 ---
-stage: none
-group: unassigned
+stage: Plan
+group: Project Management
 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/#designated-technical-writers
 ---
 

doc/api/personal_access_tokens.md

 ---
-stage: none
-group: unassigned
+stage: Manage
+group: Compliance
 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/#designated-technical-writers
 ---