Use iw to allow wifi-connect to refresh networks while connected

[meelash]

This is an improvement on https://github.com/balena-os/wifi-connect/pull/492. I found on my raspberry pi 4 hardware/software configuration that Network Manager's list of networks did not update after calling iw. The list of access points from network manager while in AP mode was just the AP ssid itself. Therefore, I updated the code to use iw's response to populate the network list live when the AP has been created. Of course, I had to use a version of wifiscanner that included the security information from iw for linux. The wifiscanner repo had a pull request by @booyaa that added it.

[hupster]

Works well for me. Merged upstream changes in this branch.