Server should have a bootstrap::wifi_list route that returns the list of available networks

[rschulman]

There should be an endpoint available via GET that takes no arguments and returns a JSON object that is an array containing objects, one per available wifi network, consisting of:

• SSID: a string containing the name of the network
• encryption: a string consisting of one and only one of the following: None, WEP, WPA, WPA2
• strength: an integer representing dBm of the network