We move all the auth handling, serialization and deserialization into a new AuthContext interface, and then standardize a registration model for handling of specific auth context types (user, robot, token, etc).
* Add flag to enable trust per repo
* Add api for enabling/disabling trust
* Add new LogEntryKind for changing repo trust settings
Also add tests for repo trust api
* Add `set_trust` method to repository
* Expose new logkind to UI
* Fix registry tests
* Rebase migrations and regen test.db
* Raise downstreamissue if trust metadata can't be removed
* Refactor change_repo_trust
* Add show_if to change_repo_trust endpoint