[Cloud] Secret keys view is inaccessible without an active instance

[Sikarii]

Currently, the view for managing secret keys (https://cloud.edgedb.com/secret-keys) is inaccessible in the UI without an active instance even though the secret keys themselves will still exist after deleting an instance because they are organization (or user?) specific.

If they're organization specific, perhaps there should be a "Secret keys" in the sidebar of an organization?