Moved themes/titanium/ and themes/starlingx/ folder from
stx-horizon into stx-gui. Renamed titanium to starlingx and
deleted titanium.
Updated the spec file so the themes/starlingx/ folder is
installed under openstack_dashboard/themes.
Story: 2004552
Task: 28310
Change-Id: I328df72bca0c8d5288a36a5257cf5738eba622da
Signed-off-by: Kristine Bujold <kristine.bujold@windriver.com>