Issue #1807042 by tim.plunkett, effulgentsia: Rename entity storage/list/form/render controllers to handlers, part 1: organize existing annotation keys.
Issue #1849752 by effulgentsia, Berdir, jibran, neclimdul: Abstract non-Drupal-specific parts of AnnotatedClassDiscovery into a Drupal\Component base class.
Issue #1782244 follow-up by sun, znerol: Fixed Convert image styles array into ImageStyle (extends ConfigEntity).
Issue #1806178 by tim.plunkett, beejeebus: Remove code duplication for hook_config_import_()*() implementations of config entities.
Issue #1763974 by tim.plunkett, EclipseGC, berdir, xjm, neclimdul, FabianX: Convert entity type info into plugins.
Issue #1782244 by heyrocker, andypost, tstoeckler: Convert image styles array into ImageStyle (extends ConfigEntity).