Add basic Wi-Fi usage examples.

[beriberikix]

Currently the only general example for Wi-Fi is a Wi-Fi Shell. There's also a board-specific one for Espressif, though it's probably generalizable.

It would certainly be great to have more examples beyond the shell. AP, STA & Dual mode would be good. I also think WPA Enterprise is increasingly common (and I see it on the Backlog.) I'm also not sure if this is in scope but it would be good to show an example of using a Wi-Fi modem as a network coprocessor, like the ESP-AT driver. I'm uncertain if there's a generalized approach like the newer Modem subsystem, but it's a common scenario to document.

Related but probably out of scope would be some sort of Wi-Fi device provisioning example. I think it may actually need to be a library but could start as a webserver + softap. See Nordic and Espressif for reference.

[jukkar]

For example the sta-ap sample from espressif boards directory https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/boards/espressif/wifi_apsta_mode looks pretty generic to me, I think it could be moved to samples/net/wifi directory, and the wifi-shell to have its own sub-directory there, like samples/net/wifi/shell

[krish2718]

I am trying to add Zperf + Wi-Fi support, exploring two options:

1. Add an overlay-zperf.conf to the samples/net/wifi/shell (and board specific tuning in the boards directory)
2. Add an overlay-wifi-hostap.conf to the samples/net/zperf (and board specific tuning in the boards directory)

I don't have any preferences, but as primary usage is Zperf, I am leaning towards option#2 any opinions?

[beriberikix]

+1 on option #2 from me as well.