Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1890784 by alexpott, YesCT, heyrocker, tim.plunkett, EllaTheHarpy, beejeebus: Refactor configuration import and sync functions.

Issue #1821848 by andypost, rbayliss, alexpott: Fixed Move image style load/update/delete operations into a new ImageStyleStorageController.

Issue #1852966 by yched, Stalski, zuuperman, swentel: Rework entity display settings around EntityDisplay config entity.

Revert "Issue #1852966 by yched, swentel: Rework entity display settings around EntityDisplay config entity."

This reverts commit 8ad67af2.

Issue #1852966 by yched, swentel: Rework entity display settings around EntityDisplay config entity.

Issue #1782244 by heyrocker, andypost, tstoeckler: Convert image styles  array into ImageStyle (extends ConfigEntity).

Issue #606598 by andypost, stBorchert, sun, aspilicious, joachim: Added Human readable image-style names.

Issue #1508872 by attiks, disasm, Alan Evans, Jelle_S, marcingy, sun: Fixed Image effects duplicate on edit.

Issue #1446464 by cfennell, Berdir, aaron, tim.plunkett: Get rid of file_field_load() - shouldn't load all file object data with field load - only file ID.