Authentication: cache plugins for auth and their settings in the auth_registry. - Before that change on each requests 4x we loaded plugins for authentication, this hit many caches, db invalidation context and loaded the plugins logic each time. This was a heavy performance hit for SVN and other backends as they needed to load that plugins many many times - Since Authentication plugins almost never change, we'll not store the plugins listed for authentication into the authnregistry for each process - For AuthPlugins settings we now also flush plugins settings, and authnregistry cached plugins