Branch Cleanup

[canny]

Once a PR is merged into main/master or closed, I would like the ability to delete all pacts associated with that branch because that particular pact should either exist in production or will become the baseline pact for future development.
Currently this is especially cumbersome because of things like renovatebot for github actions automatically creating a lot of PRs in our workflow, so it quickly is cluttering up Pactflow and makes it hard to see the contract (on main) that we care about.

https://pact.canny.io/admin/board/feature-requests/p/branch-cleanup

[canny]

This issue has been linked to a Canny post: Branch Cleanup 🎉