UI: Allow selecting domain and account for VNF appliance deployment

### The required feature described as a wish

I can select the domain and account, for instance deployment in the UI, but the same is not visible for the VNF appliance deployment page. It would be nice to have it added. It works otherwise via API/CMK.

Start at the VNF appliance deployment page in the UI and compare it with the instance deployment page, where domain and account selection are already available. Verify the corresponding API/CMK behavior while tracing the UI flow; done means both selectors are visible and usable for VNF appliance deployment.

Written by the indexing model from the issue text.