Improve the shell's 'status replication' command output

The output of the shell's 'status "replication"' command could use some cleaning up.

The basic format is:

version VERSION
N live servers
SERVER_1:
SOURCE: PeerID=PEERID, AgeOfLastShippedOp=160347, SizeOfLogQueue=49, TimeStampsOfLastShippedOp=Thu Mar 25 01:55:21 UTC 2021, Replication Lag=161013
SINK : AgeOfLastAppliedOp=0, TimeStampsOfLastAppliedOp=Thu Mar 25 01:49:53 UTC 2021
...

Issues:

• Per line format is KEY=VALUE, ... . Most KEYs are CamelCase but some have spaces. Should all be camel case for consistency.
• Age is printed as long and timestamp is string (local TZ) format. I think the string formatting of the timestamp makes it difficult to read. Lets just print timestamps as longs. Or provide a non-default option for string formatted timestamps.
• There is no sense of effective rate or bandwidth. Each source and sink line emitted should provide some sense of current workload: rpcs/sec, bytes/sec, cells/sec... something.