Issue #2282119 by amateescu, jibran, Jo Fitzgerald, yched, plach, timmillwood, fago, Sam152, larowlan: Make the Entity Field API handle field purging

Issue #2391829 by amateescu, cilefen, Berdir, yched, fago: ContentUninstallValidator relies on the not required ContentEntityStorage::hasData() method

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

Issue #2338873 by plach, fago, effulgentsia, swentel: Modules providing non-configurable field storage definitions can be uninstalled, leaving orphaned unpurged data

Issue #2335879 by alexpott, dixon_, Wim Leers, chx, mauzeh, ygerasimov, jeqq: Change SqlContentEntityStorageSchema::requiresEntityDataMigration() to ask the old storage handler if it has data rather than assuming yes unless NULL storage

Issue #2100343 by Berdir, fago, martin107, visabhishek, sriharsha.uppuluri, Yorirou: Remove 'fieldable' key in entity definitions in favour of 'field_ui_base_route'.

Issue #2333113 by effulgentsia, plach: Add an EntityDefinitionUpdateManager so that entity handlers can respond (e.g., by updating db schema) to code updates in a controlled way (e.g., from update.php).

Issue #2144263 by fago, yched, alexpott, Berdir, plach, andypost, effulgentsia, michaelfavia: Decouple entity field storage from configurable fields.

Issue #2200821 by yched, plopesc, Berdir, claudiu.cristea, swentel: Rename Fieldinterface and FieldInstanceInterface.

Issue #1497374 by yched, chx, amateescu, plach, Damien Tournoud, fago, swentel: Switch from Field-based storage to Entity-based storage.