Need to define a PoC NetReach Agent profile to prove out extender device operation

[craigpratt]

We need to define and implement a NetReach Agent for use on extenders.

Essentially this should be a slimmed-down NetReach agent which has the following:

o The hostapd adapter (for configuring the hostapd WPA PSK entries)
o NetReach adapter support for extender provisioning (an example HTTP endpoint to allow setting of the backhaul SSID and passphrase)
o NetReach adapter support to only perform the Extender-specific initialization and operation (setting up the backhaul Station AP and bridge it to the hostapd AP)
o PSK lookup caching