* Remove app/include/netif/wlan_lwip_if.h
This file appears to be unused in our tree.
* New `net.if.info` call to show LwIP information
This is a generalization of `wifi.sta`'s and `wifi.ap`'s `getip` and
`getmac` calls. I don't propose to deprecate those, but perhaps we
should, in the documentation, point users at this function instead.
The direct motivation is to permit continued use of DHCP-provided NTP
servers in a future where
https://github.com/nodemcu/nodemcu-firmware/pull/2819 has landed, now
that https://github.com/nodemcu/nodemcu-firmware/pull/2709 is in the
tree. But rather than exposing just that information, a more general
interface seems useful.