Initial changes to tweak layout.

- Adding DeviceProfile callback for when the launcher layout changes due
  to insets.  This is necessary since there are now different layouts
  depending on which side the navigation bar is on
- Consolidating hotseat and other layout into the device profile 
  launcher layout logic
- Making the all apps icons match the workspace icon height
- Tweaking caret drawable to draw to the bounds specified to simplify
  layout in each orientation
- Fixing minor issue with page indicator shifting in landscape
- Centering overview buttons to the workspace page

Bug: 30021487
Change-Id: I1866bce00b2948f3edd06168c0f88d81207e3f13