Shotgun now uses python-cliff to provide
CLI like:
shotgun2 snapshot --config /path/to/snopshot_config.yaml
This change will allow us to add other subcommands
like "shotgun2 report" that is to be used for gathering
short report about the master node (instead of version.yaml)
Previous version of shotgun CLI is still available
and deprecated.
Change-Id: I3bc1f711d0e0fcf06f9414df1533d641a0e46595
Related-Bug: #1515517