Add optional flag to clear old preloaded workspace

Adds an optional extra to the PRELOAD_WORKSPACE broadcast receiver, that
when set to true will clear the database of any previously loaded workspace
if needed.

All new code is guarded by this extra and will only be triggered by the EDU
NfcProvision adding this new flag.

This will allow EDU provisioning flow to override any previous preloads set
by gservices.

Bug: 13474473
Change-Id: I973c613c4ca024de18ba57a903f4a5d78cbdfc98
3 files changed