Expanding Documentation

[rvbcldud]

Hello there!

I have been playing around in smoltcp and seem to have finally got a grasp on how the innards function. The extensive documentation already available was a huge help. However, it still required a lot of experimentation and looking through the code base (some of which is inevitable & due to a lack of experience on my part).

One repository that I found in my research was one by smoltcp's very own @thvdveld: RPL Docs. More specifically, the Using smoltcp and Adding sockets pages.

All this is to say, I think it would be helpful to add some more docs helping someone who is not as familiar with embedded devices (myself) such as ones similar to the previously mentioned. Additionally, an explanation of the token system would be helpful.

Let me know what you think! Good idea? Bad?

Thanks!