Themes: Let ThemeService handle all theme processing [1/3]

Only themes that are applied will be processed inside of the
PackageManagerService, all others will be sent off to the
ThemeService.

Change-Id: I5f2ec628e1d22a05accc6727efb0c1387455f82f
[1/2] Immersive mode: option to disable force navbar when ime shows

Change-Id: I6ebeceb7e87084f0eeb47215aa837bf26d0d1f63
Update the volume panel color to match Hover

The volume panel slides in from the top currently making it look similar to Hove
r. As both the elements slide down from the top, there should be consistency in
terms of design.

Change-Id: Ifa4439f593b390014a3efb672bc2d00eef6fb869