WIP: Chore/new docs

[ricricucit]

@noandrea this is what I would also use as a template for other SDKs docs.

I still want to add some features, namely:

1. Info about creating a keypair
2. How to add tokens (faucet URL)

See #340 for more info

[ricricucit]

@Pegahbit, since you've been putting effort into Documenting other projects:

Is there anything important I am be forgetting?
Do you have any tips on how to make this better?

Thanks!