Issue #2198377 by alexpott: Enforce UUID key name in configuration entities.

core/includes/entity.inc

core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php

...lib/Drupal/Core/Config/Entity/ConfigStorageController.php

..._block/lib/Drupal/custom_block/Entity/CustomBlockType.php

core/modules/block/lib/Drupal/block/Entity/Block.php

...es/breakpoint/lib/Drupal/breakpoint/Entity/Breakpoint.php

...eakpoint/lib/Drupal/breakpoint/Entity/BreakpointGroup.php

.../config/lib/Drupal/config/Form/ConfigSingleExportForm.php

.../config/lib/Drupal/config/Form/ConfigSingleImportForm.php

...s/config/lib/Drupal/config/Tests/ConfigEntityUnitTest.php

.../lib/Drupal/config/Tests/ConfigSingleImportExportTest.php

...ig_test/lib/Drupal/config_test/Entity/ConfigQueryTest.php

.../config_test/lib/Drupal/config_test/Entity/ConfigTest.php

core/modules/contact/lib/Drupal/contact/Entity/Category.php

core/modules/editor/lib/Drupal/editor/Entity/Editor.php

...les/entity/lib/Drupal/entity/Entity/EntityFormDisplay.php

...odules/entity/lib/Drupal/entity/Entity/EntityFormMode.php

...les/entity/lib/Drupal/entity/Entity/EntityViewDisplay.php

...odules/entity/lib/Drupal/entity/Entity/EntityViewMode.php

core/modules/field/lib/Drupal/field/Entity/FieldConfig.php