[FIX] rma: do not force reservation on supplier RMA deliveries

* remove code call to unexisting `force_asign`.
* only one model per model file and rename as appropriate.

rma/models/__init__.py

@@ -1,13 +1,12 @@
-# License LGPL-3.0 or later (https://www.gnu.org/licenses/lgpl.html)
-
 from . import rma_order
 from . import rma_order_line
 from . import rma_operation
-from . import stock
+from . import stock_move
 from . import stock_warehouse
 from . import product
 from . import product_category
-from . import procurement
+from . import procurement_group
+from . import stock_rule
 from . import res_partner
 from . import res_company
 from . import res_config_settings