If we are putting this into a `shared`component, I would like to use the occasion to apply it a little more into FTU:

on `ftu/js/wifi.js`:
we could transform `init:
if ('mozWifiManager' in window.navigator) {
      this.api = window.navigator.mozWifiManager;
[...]
` into `init:
this.api = WifiHelper.getWifiManager();
[...]`

so we can get rid of all the checks `if ('mozWifiManager' in window.navigator)`on the code, and the duplicated declaration of `fakeNetworks`(line 54)

What do you think?