ui: adding discover host integration to AddHost view

This patch adds sublist under AddHost to allow picking and provision
foreman hosts.

Wiki: http://www.ovirt.org/Features/AdvancedForemanIntegration

Change-Id: I0faf667019760326019368f044ee16265d41a620
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1083993
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>