Document kcmscli

`kcmscli` is a tool that can be used to locally manage k8s-cms deployments. However, it is not well documented:
- how to install `kcmscli`
- how to setup `kcmscli`
- quickstart on using `kcmscli`
- detailed docs on various sub commands, options

The tool already has some documentation when using the `--help` flag. We should collect the documentation to make it easier for users to find