Policy Templates for Firefox 62 and 60.2

UPDATED: Bookmarks are fixed. Sorry about that.

New policies include:

Hardware Acceleration
Permissions (Camera, Microphone, Notifications, Location)
Additional Bookmarks
Remove Search Engines
Custom Update URL

We've also made all policies work on rapid release except for the search
engine policy.

On Window when using GPO, some of these policies are now machine only. This
is documented in the README.md and in the policies themselves. We did not
remove them from User Configuration because they can still be used there on
the ESR.

All of these changes have been uplifted to 60.2 ESR as well.