Add sncast 101 section

[cptartur]

It should be a very high level guide walking through steps of using sncast.

1. Creating or importing account
2. Declaring a contract
3. Deploying a contract
4. Calling a contract
5. Invoking a contract
6. (Maybe) multicall

This should NOT go into details of any of these functionalities. It should link to relevant sections of proper docs instead.

[augustin-v]

I am applying to this issue via OnlyDust platform.

My background and how it can be leveraged

Hi, I'd love to work on this and make my first Only Dust contribution. I've contributed to the Aptos documentation in Japanese before, and I'm eager to get more deeply involved with Starknet.

[onlydustapp]

Hey @augustin-v!
Thanks for showing interest.
We've created an application for you to contribute to Starknet Foundry.
Go check it out on OnlyDust!

[onlydustapp]

Hey @augustin-v!
Thanks for showing interest.
We've created an application for you to contribute to Starknet Foundry2.
Go check it out on OnlyDust!