FEATURE: Create subcommands for system wide operations

[Masber]

Create a new subcommand section system to manage sites:

manta system <verb> <operation> <CFS configuration name> <role or subrole name>

eg:

manta system set runtime-configuration my-config-v1 alps

These commands will apply to all nodes belonging to a specific role or subrole

Candidates:

manta system set runtime-configuration
manta system set boot-confguration
manta system set boot-image
manta system set kernel-parameters
manta system power reboot
manta system power on
manta system power off

This command should not be operational to users and backend should check if user has access to these operations

Benefits:

• No need to destroy/modify/move nodes in users' HSM groups
• Wide site operations simplification

NOTE:
The subcommand proposed system is not final and other names like site could also be used. This is an open discussion.