Add documentation for Arduino MKR 1310

[LDannijs]

Summary

Add documentation for Arduino MKR 1310

Why do we need this ?

The device is quite popular for makers who want to try LoRaWAN, but we do not yet have documentation for it.

What is already there? What do you see now?

No documentation for the Arduino MKR WAN 1310 at all.

What is missing? What do you want to see?

Arduino themselves already have a guide: https://docs.arduino.cc/tutorials/mkr-wan-1310/the-things-network/

How do you propose to document this?

Adding instructions for how to onboard the MKR WAN 1310 and maybe add an example project to it.

Can you do this yourself and submit a Pull Request?

Yes, @KrishnaIyer