[cli] list-reputation-commitments

[brenzi]

In order to track faucet activity (and other personhood benefits), we need to see recent reputation commitments.

must accept --at argument

for encointerReputationCommitments.purposes:
  print purpose (i.e. ectrfct0PioneerPot)
  for cid
     print cid
     for cindex
        print "cindex: <number of accounts>"
     print total unique committers and total number of commitments for cid
  print total unique committers and total number of commitments for purpose 

this only returns final numbers if queried on the last block of the attesting phase for the cindex which will be purged. commitments can be made at any time for any cindex within reputation lifetime

[brenzi]

closed in #368