Issue #2005716 by tim.plunkett, msonnabaum, dawehner, alexpott, effulgentsia: Promote EntityType to a domain object.

Issue #2148709 by amateescu, xjm: CommentManager::getFields() should not try to get fields for config entity types.

Issue #2066535 by tim.plunkett, jsst, Berdir: Add EntityManagerInterface and stop typehinting with EntityManager.

Issue #2098011 by larowlan: Support dynamic route parameters to enhance comment admin paths with entity type and field name from comment bundle.

Issue #731724 by larowlan, andypost, dixon_, tsvenson: Convert comment settings into a field to make them work with CMI and non-node entities.