[Bouncer] Move bouncer title to bottom.

Move bouncer title to the bottom. Add some custom dimensions for
portrait versus landscape.

Fixes: 256786970
Fixes: 257025163
Test: Tested pin/password/pattern view landscape/portrait on reg and largest display
size. UserSwitcher mode only applies to tablet right now.

Change-Id: Iba4a668d17ff1cfa3f6fcfabacb4af4b374321f3