Cannot set default git ACLs for a team

This is a feature request.

git-ubuntu is maintaining a very large number of repositories, and it's looking like we're going to need to start using ACLs in some fashion to maintain a staging area (see also bug 1993290).

I'd like to be able to specify a "default" git ACL at team level, which would apply if no specific ACLs are set against a specific repository. This way, I wouldn't have to have the git-ubuntu importer maintain a separate ACL for every repository that is essentially the same. Further, if we implement staging branches using something like the ~ubuntu-uploaders team namespace, then repositories won't necessarily exist until there is something staged; having a default would allow the ACLs to be immediately correct without having to require the ACL to be individually set at the time the staging takes place, making the workflow easier for uploaders.

I imagine the default would need to be on a per-target-distribution basis, so something like "repositories owned by team X that have a target in the Y distribution should act as if they have ACL entries Z1 and Z2 except where they have per-repository ACLs set explicitly"