Documentation for all supported commands

[sids-b]

Documentation for all commands supported by the ci-bot for easy usability by the user.

[sids-b]

@edisonxiang , @pavan187 @swx457056 , Can we quickly come up with a document of all commands supported by ci-bot. Very glad that the bot is working on kubeedge repo now. Thanks All.
cc @m1093782566

[m1093782566]

Sushantha just talked to me that CNI-Genie want to use ci-bot. So, a document for deploying is needed as well.

[sids-b]

@swx457056 , @pavan187 , Any update on this ? Need a document