Add "Teach Yourself Web3" to the tutorials section

[joaostein]

This PR includes the "Teach Yourself Web3" resource in the Tutorials section. It's a free & structured learning experience designed to help experienced developers acquire foundational knowledge to start their path to becoming Web3 engineers.

Checklist

• [ x ] The URL is not already present in the list (check with CTRL/CMD+F in the raw markdown file).
• [ x ] Each description starts with an uppercase character and ends with a period.
  Example: solc-js - JavaScript bindings for the compiler.
• [ x ] Drop all A / An prefixes at the start of the description.
• [ x ] Avoid using the word Solidity in the description.

[bkrem]

Thanks for the addition! 🙌