Fix unwanted client config generation

The current mechanism is messy after a while..

[ ] If no permanent configuration was requested, a default config should be chosen
[ ] unless there is none - then start with an empty clientconfig that does only get stored on request
[ ] There should be an option in the user actions to make a clientconfig permanent, once logged in
[ ] The "Stay logged in" checkbox on login should make a clientconfig permanent, as well

Hackerfleet / hfos-legacy