Default workspace improvements
This reverts commit b54b34e

Fix bug for mdpi devices crash loop.

Revert requires overlays to know if GSF installed,
adding a run time check to load default workspaces.

Add in additional overlays per density for new LauncherModel
and LauncherProvider 4.4.3 logic.

Change-Id: I5709182521e80d273e892eb3310abd68acac95ad
Cleanup and fixes

Change-Id: I7f97e893e0de9cf6cb517dab0475bfbd75516129