Allow server_id to be defined in replica set member config

[estolfo]

It'd be great if you could define a server_id for a member in a replica set. For example, the payload for a POST request to /replica_sets would look like this:

{
  "members": 
     [ {"rsParams": {"priority":1}, "server_id": "serverA",
       {"rsParams":  {"priority":0}, "server_id": "serverB",
       {"rsParams": {"arbiterOnly":true}, "server_id": "serverC",
     ]
}

And then you could send commands (stop, start, restart) to the uri /servers/serverA

[llvtt]

Available as of 27a05cfcda8d3bf23fb22f4a329096effd3e59fd! The format for the requests is as you describe. For shards, replica set member ids may be given in the key rs_id. All server ids are given in server_id.

[estolfo]

sweet, thanks @lovett89 !!