userportal, webadmin: Latest template instace safe recognition

Regular template and latest template (the one pointing to the lates
version) were recognized by matching of localized UI name.

This patch introduces frontend only class LatestVmTemplate to mark
latest templates.

Change-Id: I161f1d9603ea17ef7fc3801eb3dfa0cb924af2b4
Bug-Url: https://bugzilla.redhat.com/1166152
Signed-off-by: Jakub Niedermertl <jniederm@redhat.com>