Add a config parameter to limit the number of active branches

[jeremystretch]

Plugin Version

v0.4.0

Proposed functionality

Introduce a new configuration parameter (e.g. max_active_branches) to limit the permitted number of active (non-merged) branches. This would complement the max_branches parameter introduced in v0.4.0, which limits the total number of branches.

It might also make sense to introduce a per-user variant of this parameter.

Use case

It may be desirable to limit the number of active branches, either globally or on a per-user basis, to avoid the build-up of abandoned work. This parameter would allow an administrator to enforce a limit on active branches without constraining the total number of branches in the database.

External dependencies

No response