Add links to feature flag YML

Adds extra info to feature flag YML files

config/feature_flags/development/broadcast_issue_updates.yml

 ---
 name: broadcast_issue_updates
-introduced_by_url: 
-rollout_issue_url: 
-group: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/30732
+rollout_issue_url: https://gitlab.com/gitlab-com/gl-infra/delivery/-/issues/1210
+group: group::project management
 type: development
 default_enabled: false

config/feature_flags/development/dashboard_pipeline_status.yml

 ---
 name: dashboard_pipeline_status
-introduced_by_url: 
-rollout_issue_url: 
-group: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/22029
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/209061
+group: group::continuous integration
 type: development
 default_enabled: true

config/feature_flags/development/real_time_issue_sidebar.yml

 ---
 name: real_time_issue_sidebar
-introduced_by_url: 
-rollout_issue_url: 
-group: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/30239
+rollout_issue_url: https://gitlab.com/gitlab-com/gl-infra/delivery/-/issues/1210
+group: group::project management
 type: development
 default_enabled: false