Add flag to enable trust per repo (#2541)

* 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

data/model/repository.py

@@ -279,6 +279,11 @@ def unstar_repository(user, repository):
      .execute())
   except Star.DoesNotExist:
     raise DataModelException('Star not found.')
+  
+  
+def set_trust(repo, trust_enabled):
+  repo.trust_enabled = trust_enabled
+  repo.save()
 
 
 def get_user_starred_repositories(user, kind_filter='image'):