Make branch filtering a common behavior between the disk and remote loaders
A further step would probably be making the branch filtering policy properly configurable, rather than hard-coded in these functions. That way, we can decide that we do want to archive all the branches from an archived repo, rather than just the "live" branches that we'd commonly archive from remote repositories.
Depends on !39 (closed).
Test Plan
existing tox test moved to the common test scaffold
Migrated from D3189 (view on Phabricator)