[MIG] report_label

[IMP] allow to create report.paperformat.label without creating each time report.paperformat item
[FIX] Remove useless data that are specific Label: Agipa 114016
[REF] simplify UI, removing custom entry for ir.actions.server
[ADD] migration script to migrate name field
[IMP] Add label_background_color to allow to easily define background-color for label. (That can be usefull to debug label positions)
[DOC] update screenshots to new V16 versions
[IMP] Set body and html margin to 0 to to able to be predictive when designing a label sheet
[IMP] replace style by class in the label template, reducing the size of the html code generated.
[IMP] replace label_template by label_template_view_id on the ir.actions.server model, removing useless xml and python code. (provide migration scripts)
[REF] Split wizard file into wizard and wizard line file, following OCA guidelines

report_label/tests/test_report_label.py

@@ -22,6 +22,6 @@ class TestReportLabel(common.TransactionCase):
                 "discard_logo_check": True,
             }
         )
-        wizard = self.env[model].with_context(context).create({})
+        wizard = self.env[model].with_context(**context).create({})
         report_action = wizard.print_report()
         self.assertEqual(report_action["type"], "ir.actions.report")