Mix snapshots and images tables together

Don't filter snapshots from images data, display image_type column in images table,
don't translate image string in get_image_type method, don't show LaunchImage button when
image is in different state than active, remove snapshots table from the UI, update tests

Fixes: bug #1140760

Change-Id: Ie6cc5bc98fa97de00b55540fe9f60e90d20acab3
Merge "Mix snapshots and images tables together"