network: add freebsd backend

[charlesrocket]

This adds a native FreeBSD backend for the network module. Tested with network.qml/widget.

[cpwrs]

Is there a reason to use wpa_cli instead of the control interface directly?
https://w1.fi/wpa_supplicant/devel/ctrl_iface_page.html

wpa_supplicant is a valid backend for linux as well. Is there other networking stacks for FreeBSD? If so, this should probably be the FreeBSD impl of the wpa_supplicant backend and not the other way around.

I was planning on adding IWD as a backend eventually, which is a similar problem. I think that these backends should cover only the portion of the API they can support alone. For example, the Linux IWD backend wouldn't use udev to list non-wireless devices.

[charlesrocket]

I used CLI because I am familiar with it. Right now I just want the current FBSD PRs merged, then I can start improving these modules.

[charlesrocket]

After the second and obviously deliberate line cut, I am done with this circus.