oidc-agent client owner not indicated

[maarten-litmaath]

When an oidc-agent client is registered e.g. via the device flow, it becomes associated with whomever approved the request, but that identity is not shown in any of the tabs for that client on the clients page, whereas a VO admin needs to be able to see on whose behalf a given client is operating, e.g. to be able to decide if certain scopes are appropriate for that client or not.

The current proposal is to add a new tab which provides that identification.

[maarten-litmaath]

The approver should (also) be made to appear under the "Owners" tab.