Implement support for nmcli

[falkecarlsen]

As I've switched to Fedora, I now use networkmanager and therefore nmcli for configuring both wired and wireless network connections.

This should TM be fairly straightforward as it seems that the netctl actions currently used can be straightforwardly be mapped. However, some functions should be guarded for compatibility reasons, e.g., reading profiles from /etc/netctl/ as this only applies to netctl-systems.

The mapping could look like this:
sudo netctl start $profile -> nmcli con up $profile
sudo netctl stop $profile -> nmcli con down $profile
sudo netctl stop-all -> ?
sudo netctl restart $profile -> ?
However, profile-creation and connection is possible as a one-liner under nmcli
? -> nmcli device wifi connect $SSID password $password - this seems to update an existing SSID's password as well, being another way to trigger a daily-password update on an SSID.

Note, $profile for nmcli can be either SSID or UUID, which could be pretty nifty.