This moves the netdev/netlink namespace out of drivers and into their
own packages. Also, defines netdev and netlink as L3/L4 and L2 OSI
layers, respectively. Move some L3 functionality from netlink to
netdev (GetIPAddr).
For netlink, add ConnectParams for NetConnect to pass in L2 connection
parameters (ssid, pass, auth_type, etc). Also adds connection mode
(STA, AP, etc).
For netlink, add SendEth and RecvEthFunc funcs to handle L2 send/recv of
Ethernet pkts.