[REF] Move python object files to models folder

product_usability/__init__.py

@@ -1,3 +1,3 @@
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
-from . import product
-from . import pricelist
+from . import models

product_usability/models/__init__.py

@@ -0,0 +1,4 @@
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from . import product
+from . import pricelist