network: support cloned-mac's new value stable-ssid (WiFi only)
NetworkManager has a new special value for cloned-mac which is "stable-ssid" (only for WiFi). It creates a MAC address based on the WiFi network's SSID, so it is used always you connect to that SSID, even if the NM's connection is deleted and created again.
This new value is being proposed as default in Fedora: https://discussion.fedoraproject.org/t/f40-change-proposal-wifi-mac-randomization-system-wide/99856. The goal is to increase user's privacy but still allowing connecting to networks with MAC filtering out of the box.
Right now, if stable-ssid is configured, either via CLI or as default via *.conf file, it is shown as an error in g-c-c. It would be nice to support it, specially if it becomes the default in Fedora because otherwise g-c-c will show the distro's default as an error.
The change is proably very trivial, but for reference, this is the patch to nm-connection-editor: network-manager-applet!143 (202149c0)