Implement QR code so users can easily connect to WiFi hotspot

[gnarea]

When syncing with people, it'd be ideal to allow the courier app user to generate a QR code that gateway users can scan to connect to the hotspot network.

Here's one potential way to get the name and password of the network, but we're not sure it'd work in the latest versions of Android: https://stackoverflow.com/questions/25173596/android-get-ssid-and-password-of-a-phone-which-is-a-portable-wifi-hotspot