Improve the layout of the wi-fi list
Currently the wi-fi list looks like this:
In #554 (closed) there was some discussion about this. In particular @bertob didn't like the gaps on the right for unknown networks.
After going back and forth on it for a while, we came up with the following design:
The idea is to use a small custom lock icon, which is shown next to the wi-fi strength icon to indicate whether the network is encrypted. This is intended to avoid us having to maintain an additional set wi-fi icons for encrypted networks.
The sorting of the list has already been dealt with in #736 (closed).