add support for NXP Wifi in RW612, in an example

[scaprile]

There are no pubic docs for the Wi-Fi hardware
There are no pubic docs for the Wi-Fi firmware
There are no pubic docs for the Wi-Fi libraries. The lowest level seems to support baremetal operation, but higher levels use some form or RTOS, be it FreeRTOS or Zephyr.
Libraries seem to be a mix of prior libraries, written for different chips/modules through the years, all intertwined together; execution jumps freely from here to there.

This has been done using FreeRTOS, and avoiding vendor overhead as much as possible.

Things to check for review (what is not vendor code):
example:
source/ : main example file, as usual
wifi/port/net/net.c : what vendor code sees as a TCP/IP stack, Mongoose-style; modified vendor code for lwIP
wifi/port/net/netif_mongoose.c : the interface to vendor code, Mongoose-style; based on vendor example code
mongoose:
src/driver/nxp_wifi.*: a thin layer over the above, to avoid static -> global and keep sanity. Most work is not here, as everything depends tightly on vendor code

NOTE: Cube tests failure --> deploy new Wizard code required
NOTE: Pico W and Pico 2 W tests failure --> #3266