[Fingerprint] Add fingerprint enroll in setup wizard

Make a subclass for each enrolling screen that setup wizard uses, and
in override the corresponding get*Intent methods to always use the
setup wizard versions of the next screens.

On minor change made to the original flow is that it will now return
RESULT_OK if it is finished, as opposed to RESULT_CANCELED.

Bug: 21695577
Change-Id: Id666826e8027272ede6a5426967d66fb291670a4