Issue #2994398 by tim.plunkett, phenaproxima, vmilic, Berdir, Wim Leers, tedbow, bradjones1: Not properly clearing EntityFieldManager's fieldMap leads to fatals, often after migration or bundle creation

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2337191 by tim.plunkett, dawehner, jibran, yched, Wim Leers, catch: Split up EntityManager into many services