MB-8220: Provide aggregated report

Report will contain total vbuckets, msgs, bytes that are recovered.
Sample report:
 Recovery :                Total |    Per sec
 batch    :                   13 |       14.5
 byte     :                  140 |      156.0
 msg      :                   14 |       15.6
4 vbuckets recovered with elapsed time 0.90 seconds

Change-Id: I3e05f3f34a6a4011be6f1ca2d04eac0a48ac7eef
MB-8228: Fix a merge error for healthchecker

Change-Id: I41e7a2f48241eb4ef03422ed08c3f8f592192574