Add option to always auto-update

It would be nice to have an option to always auto-update Northstar on FlightCore launch similar to what for example [Viper](https://github.com/0neGal/viper/) does. Not auto-updating without user input was a design decision taken to avoid overriding exsiting (dev) installations. However for some end-users, not having to manually press the _Update_ button may be preferred. As such we should have some way to offer that option for that subset of users.