webadmin: action to commit brick removal operation

Added a new 'Commit' action to 'Remove' action group in the
Bricks subtab.

On Clicking, a confirmation will be shown with list of bricks
which is being removed. Upon the confirmation the bricks
will be removed from the volume.

Change-Id: I1048150ca4b994766a09d0a4a1b1d33065051c65
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>