chore(docs): Solidity Learning Journey

[signorecello]

Description

As part of DevRel's work on Learning Journey's, this PR improves them.

Problem*

Relates to this DevRel issue

Summary*

• Puts the "Creating a Project" and "Project Breakdown" pages inside a dropdown called "Hello Noir"
• Refactors the Solidity Verifier How-To to include a Remix IDE verification example with images and more context
• Refactors the Noir landing page to incorporate a "Noir Basics" role, improves UI, adds a header image and a tabs feature, and favouring links to awesome-noir instead of hardcoded library examples
• Refactors the Homepage with buttons to immediately start the Solidity Learning journey

Additional Context

Here's the Solidity Learning Journey. For now only 3 levels deep, assuming the user would have enough autonomy to proceed after the 3rd page. This will be reassessed in the future.

[signorecello]

Could use @jzaki's Solidity knowledge to double-check the guide :)

[github-actions]

🚀 Deployed on https://65ae64e29aff340088e3d82f--noir-docs.netlify.app

[critesjosh]

Did you have trouble updating to Docusaurus 3? I tried to update the Aztec docs but ran into a ton of parsing errors due to the update to MDX v3. Mainly relating to invalid character in names for autogenerated docs. Did you encounter anything like that?

[signorecello]

I updated to that version some weeks/months ago actually... And yes MDX was breaking due to some chars not being escaped (like <, {, etc)

Some other minor things as well. I also had a problem with a webpack bug, that should be fixed in docusaurus 3.1.0 so I'll eventually update to that one at least