Add auditing for system plugin changes (#14147)

Generate audit trail for changes made via system.general and
system.advanced.

src/middlewared/middlewared/plugins/system_advanced/config.py

@@ -203,7 +203,8 @@ async def __validate_fields(self, schema, data):
             ('rm', {'name': 'isolated_gpu_pci_ids'}),
             ('add', Password('sed_passwd')),
             ('attr', {'update': True}),
-        )
+        ),
+        audit='System advanced update'
     )
     async def do_update(self, data):
         """

src/middlewared/middlewared/plugins/system_general/update.py

@@ -200,6 +200,7 @@ async def validate_general_settings(self, data, schema):
             ('add', Int('ui_restart_delay', null=True)),
             ('attr', {'update': True}),
         ),
+        audit='System general update'
     )
     async def do_update(self, data):
         """