[12.0][IMP] - add new option: create_new_line_at_contract_line_renew

Add a company config option to decide whether to create or to extend contract
line at renew action

contract/migrations/12.0.5.0.1/post-migration.py

@@ -0,0 +1,7 @@
+def migrate(cr, version):
+    cr.execute(
+        """\
+            UPDATE res_company
+            SET create_new_line_at_contract_line_renew = true
+        """
+    )