Merge branch 'schmil-disallow-project-level-ruleset' into 'master'

Add environment variable to allow project level ruleset

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/158069



Merged-by: Dheeraj Joshi <djoshi@gitlab.com>
Approved-by: Dheeraj Joshi <djoshi@gitlab.com>
Approved-by: Connor Gilbert <cgilbert@gitlab.com>
Reviewed-by: Connor Gilbert <cgilbert@gitlab.com>
Co-authored-by: Schmil Monderer <smonderer@gitlab.com>