Merge branch 'oregand-master-patch-0bb1' into 'master'

Model migration and deprecation responsibilities, timelines, and tracking

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/182643



Merged-by: Denys Mishunov <dmishunov@gitlab.com>
Approved-by: François Rosé <frose@gitlab.com>
Reviewed-by: François Rosé <frose@gitlab.com>
Co-authored-by: Michelle Gill <mgill@gitlab.com>
Co-authored-by: David O'Regan <doregan@gitlab.com>