Add a confirmation page

Confirm storage selections before the install proceeds, and
try to warn users if the disk is part of a storage domain
(by looking for an LVM tag)

Change-Id: If0c099fbfbfda9bc609a024964905ee59e04280f
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1062515
Signed-off-by: Ryan Barry <rbarry@redhat.com>
Signed-off-by: hadong <hadong@redhat.com>