broken link to examplee

[schinns]

the networking example linked appears to be broken:
https://github.com/nerves-project/nerves_network#example-applications

I noticed that there is now a "hello_wifi" example now. Although this example doesn't seem to be using "nerves_network", and rather "vintage_net".

[curious-attempt-bunny]

See nerves-project/nerves_examples@0001e81

Remove the nerves_network example
It's currently out-of-date due to the switch to vintage_net. The
eventual goal is to replace it, but remove it for now to avoid
confusion.