SetupWizard: Fix status bar managing workflow

StatusBarManager uses tokens in binder connections to identify
disable records and queue each of them accordingly. New record creates
each time an application connects to StatusBarManager and tries to change
the state. New records don't activate until previous ones are destroyed.
Records can be destroyed either when app binder dies, or when the same
binder ticket reverts its previous changes.
To accomodate this behavior, StatusBarManager was moved to a static class
that initializes first when status bar gets disabled, and then gets destroyed
when status bar is re-enabled.
While we're at it, also fix race condition between main and exit activites
by moving status bar disabling code to the application class.

Change-Id: I3b33e628da1e1881181cbe665e6aaccee3dd19ef