API: Small improvements

[kiblik]

During the preparation of #9060 I noticed a couple of places which might be improved (or at least raise questions in my head):

• Missing list in FindingViewSet and ProductViewSet. Why?
• Missing update in NotesViewSet. Why? It is supported in UI.
• User should interact with API without using 1 in SystemSettingsViewSet, access should be direct.
• Move @extend_schema_view( list=extend_schema(...), retrieve=extend_schema(...),) to PrefetchDojoModelViewSet
• Missing create in RiskAcceptanceViewSet. Why? I know, there is a separated endpoint, but why not create it also directly?

[valentijnscholten]

@kiblik Is this still relevant?

[kiblik]

@kiblik Is this still relevant?

Well, the mentioned parts are still missing. And I have not received an explanation why. Some of them are really easy to implement. But I would prefer to add GHA for PR and releasing, which would describe the diff (how the related PR changes the schema or what new/changed API endpoints are in the related release). This should be done before adding new endpoints.
Btw, last can be solved in #12361, but I'm still missing feedback there.