CRUD, change add_button initialization
CRUD, change add_button initialization

* Add button now will be initialized later - only in configureAdd method
* in CRUD->init we can't use `isEditing()` method because permissions of CRUD can change later in `setModel()`
samratcis/atk4,xepan/atk4,svisystem/atk4,svisystem/atk4,samratcis/atk4,xepan/atk4,atk4/atk4,atk4/atk4,atk4/atk4,samratcis/atk4,svisystem/atk4,xepan/atk4,atk4/atk4