vdc-manage: refactor backup_storage common options.
vdc-manage: refactor keypair common options.
vdc-manage: refactor security_group common options.
vdc-manage: refactor backup_object common options.
vdc-manage: takes out default from host subcommand common opts.
vdc-manage: takes out default from storage subcommand common opts.
vdc-manage: takes out default from network subcommand common opts.