Move default os_type to misc.get_distro()

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Add os_type and os_version args to lock_many()

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Add 'lsb_release -a' parsing back to remote.OS

It can now parse either that or /etc/os-release, and remote.Remote will
attempt the latter first.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Allow mixing of bare-metal machine_types

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>