Migrate Project#owner to have OWNER membership
With !78193 (merged), new personal project owners will have
OWNER membership. We need to migrate
members records for existing personal projects too.
See https://gitlab.com/gitlab-org/gitlab/-/issues/351986#note_831687602 for numbers as of 2022/02/04.
- Get all personal namespaces and their memberships
- Create a membership for any users that are OWNER via owner_id
- Change MAINTAINER memberships to OWNER