Issue #2115145 by Berdir | effulgentsia: Move field type plugins to Plugin/Field/FieldType.

core/lib/Drupal/Core/Entity/ContentEntityBase.php

core/lib/Drupal/Core/Entity/ContentEntityInterface.php

core/lib/Drupal/Core/Entity/EntityAccessController.php

...ib/Drupal/Core/Entity/EntityAccessControllerInterface.php

...upal/Core/Entity/FieldableEntityStorageControllerBase.php

core/lib/Drupal/Core/Entity/Plugin/DataType/FieldItem.php

core/lib/Drupal/Core/Field/ConfigEntityReferenceItemBase.php

core/lib/Drupal/Core/Field/ConfigFieldItemBase.php

core/lib/Drupal/Core/Field/ConfigFieldItemInterface.php

core/lib/Drupal/Core/Field/ConfigFieldItemList.php

core/lib/Drupal/Core/Field/ConfigFieldItemListInterface.php

core/lib/Drupal/Core/Field/FieldDefinition.php

core/lib/Drupal/Core/Field/FieldDefinitionInterface.php

core/lib/Drupal/Core/Field/FieldItemBase.php

core/lib/Drupal/Core/Field/FieldItemInterface.php

core/lib/Drupal/Core/Field/FieldItemList.php

core/lib/Drupal/Core/Field/FieldItemListInterface.php

core/lib/Drupal/Core/Field/FieldTypePluginManager.php

core/lib/Drupal/Core/Field/FormatterBase.php

core/lib/Drupal/Core/Field/FormatterInterface.php