Track both framework and app overlays per package

Always bundle framework and app overlays. The old implementation, where
framework and app overlays were tracked independently, lead to an error
in the following scenario:

  1. Enable app overlay -> change reflected in app
  2. Enable framework overlay -> error: no change reflected in app
  3. Disable app overlay -> change reflected in app, including framework
     overlay

This change also leads to better architecture since the package manager
no longer needs to know that an app's overlays consist of both framework
and app specific overlays. Instead, that knowledge is handled by the
overlay manager.

Also, correct indentation in "cmd package dump packages" output and
remove obsolete constant DUMP_ENABLED_OVERLAYS.

Test: Manual
Change-Id: I707fc00052a15b22fb8c17e6155732520e6b2e52
Bug: 62680061