add command aliases

[romange]

To filter out commands sent are sent by the CP from the monitoring dashboard, we would like to support command aliases so that we could introduce say __ping in addition to ping etc.

Then in the dashboard we could filter out all the commands starting with __

[abhijat]

Are the aliases to be defined statically in the code alongside commands, or are they expected to be specified by users on the command line when starting the server, like renamed commands?

[romange]

I think command line flag is better.