HPCC-825 Change Resubmit and Restart buttons to be less confusing

Restart currently does what Resubmit used to which is reset and restart
the workunit from the beginging.  Resubmit now tries to recover the
workunit from where it left off.

Change the behavoior of Resubmit back to what it was previously,
resetting the workunit and starting over.  Add a "Recover" button which
will attempt to begin the workunit from where it previously stopped.

Signed-off-by: Anthony Fishbeck <Anthony.Fishbeck@lexisnexis.com>