main: Get rid of "SelectedProfile" property
The original idea was to have a "SelectedProfile" property that would be settable by the user, but could be different from the "ActiveProfile" if the hardware's performance mode wasn't available for example.
It turns out that having 2 separate states makes for very confusing UI, so if the performance profile becomes inhibited and it's the current one, the active profile will automatically switch to balanced and stay there.