Class CCliCommandGroup

A @carnesen/cli CLI organizes the commands as a tree where commands are the leaves and command groups are the branches. A CLI might not have any groups i.e. the root of the command tree is a command. curl is an example of a CLI with a bunch of options but just the one command. npm is an example of a CLI with many subcommands (e.g. npm install) and even sub-subcommands (e.g. npm config set). In the parlance of @carnesen/cli, the root of the npm CLI is a command group. So is its config subcommand whereas install and set are commands