docs(documentation): added guides and improved overall docs

[crisgarner]

Description

This PR started as a simple navigation improvement but ended with a bunch of improvements to our docs, heavily inspired by the documentation of great projects like Uniswap, EigenLayer, Semaphore, and others. The most notable changes are:

• Condensed redundant information in a single space.
• Moved some files to a more related category.
• Added more visibility to sections that beginners might try to check first.
• Created Guides section with multiple guides.
• Created a Getting Started page.
• Added some small UI improvements to the code blocks.

Confirmation

• I have read and understand MACI's contributor guidelines and code of conduct.
• I have read and understand MACI's GitHub processes.
• I have read and understand MACI's testing guide.

[vercel]

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Name	Status	Preview	Updated (UTC)
maci-website	✅ Ready (Inspect)	Visit Preview	Oct 17, 2024 3:05pm

[crisgarner]

There is a bunch of stuff that we can do to improve the docs, and this PR was getting big so wanted to start with this, next tasks that might be important to fix that I will make some issues are:

• Improve the Use Cases Section
• Improve some guides (Integrating)
• Some links are pointing to solidity docs that don't exist
• Remove more content that isn't required or merge it with other sections.

[kittybest]

Thanks for this huge PR! Just left some comments

[crisgarner]

Added more updates based on feedback from @kittybest @aguzmant103 @ctrlc03.

• Improved frontend guide
• Removed old content and moved around some files to a more visible part.
• Added notes on circuits compilations.

[kittybest]

Looks good to me, thanks!
And in the comment, you mentioned several possible improvements, I agree to move them to another issues and deal with them in another PR(s).