This PR adds branch rules, stored in the knotserver, which can be used to stop force pushes, direct pushes, and branch deletions. These rules are applied to branches that match at least one of a list of regex patterns and to user DIDs not present in a list of excluded users.
Corresponding issues here: https://tangled.org/tangled.org/core/issues/432 https://tangled.org/tangled.org/core/issues/454