remove embeded edit === put and add === post assumption

All actions have request methods defined in their config - the config is
modifyable, but it's not possible to change the "main" requeset method as the action classes themselves check if they are by POST/PUT.

Two common cases where the requestMethods would need to be modified, and conflict with the Crud plugin's definition:

PUT Add - When createing records with predefined ids
POST Edit - File uploads via PUT are more difficult, and API requests via PUT require "custom" handling to populate `$request->data` also.