Making the 'Allow rotation' setting dependent on system state

The setting will not be available on a tablet, where rotation is
always enabled. On mobiles, it will be disabled when auto-rotate
is disabled in display settings.
Also removing content provider dependency from settings, as its in the
same process as launcher.

Bug: 28704055
Change-Id: Ibe6b1e67411fb0e4b2e36446710f463e4a3d6883