webadmin: Add activities column to volumes tab

Add activities column to volumes tab to indicate
if there are any activities in progress on
the volume.

Depending on the rebalance status of the volume which
includes statuses like STARTED, FAILED, ABORTED and FINISHED,
corresponding icon will be shown on the activities column.

Change-Id: I9b885bfbf493958648f811966817da15036f5224
Signed-off-by: Sahina Bose <sabose@redhat.com>
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>