Enable dual wifi interfaces, one as an AP - one as the wifi

[sabhiram]

Opened to continue this reddit discussion.

Would be a pretty simple addition, although some of the code will just assume that wlan0 is the device for configuring.

Ideally we would expose these config options in the config.json file:

   "access_point": {
        "force_reconfigure": false,
        "wifi_interface":    "wlan0",
        "ssid":              "rpi-config-ap",
        "passphrase":        "zzzzzzzz",
        "domain":            "rpi.config",
        "ip_addr":           "192.168.44.1",
        "netmask":           "255.255.255.0",
        "subnet_ip":         "192.168.44.0",
        "broadcast_address": "192.168.44.255",
        "subnet_range": {
            "start":         "192.168.44.10",
            "end":           "192.168.44.50"
        }
    },

    /* New AP fields */
    "ap_interface": "wlan1",
       ... 

    },

    ... other non AP config stuff

I am thinking the server.js file can just check to see how many interfaces are supported as part of the wifi_manager's export function opening. This way any-time wifi_manager is required, we will setup the number of interfaces available.

Then, in the code which enables the AP / Wifi, we would have to check to see if we are in dual mode or single mode. Based on this mode, we would need to reconfigure the interface (or just re-enable it if we have used both interfaces before).

Thoughts?