engine: include VdsGroup virt, gluster flags in VDS entity

Added virt_service and gluster_service flags to VDS entity.
VDS view is modified accordingly to read these flags from
vds_groups table.

Change-Id: I961a37312425213fdbce446001fd2874f7661cd1
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>