chore: add recursive example

[jzaki]

Description

Adds new examples directory with recursive example from dev-rel repo.

Problem

Examples in dev-rel are not kept strictly up to date with each noir language update, so when referred to in the docs would be out of date. This code will likely need updating before automating any test as part of noir repo's CI.

Resolves #4410

Summary

There were some quirks/workarounds at the time of writing, and fixes in Noir will likely resolve those quirks (if not already).

Additional Context

A future restructure would have a new docs directory created, with the current docs moving to subfolder in that, alongside examples. So structure could be something like docs/docs and docs/examples.
PS. I presume the prettier was on default cargo fmt settings.

Documentation

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[TomAFrench]

Thanks for this. We just need to hook it up into JS workspace + tested in CI

[TomAFrench]

Assigning myself just for tracking me supporting these efforts in the Noir board.

[TomAFrench]

Also it would be good to experiment with inlining some of the text to be shown in the docs in amongst the code and using snippets to populate the doc. This would make it easier for us to keep text + code in sync.

[TomAFrench]

I'm closing this PR as we have an example which shows recursion in the examples folder. Feel free to reopen if this PR adds anything extra compared to what's in master.

[jzaki]

There are examples of the noir program which are shared, and examples of how to use them, and expected results. That is:

Noir Program	Tools to use	Expected output
in recursion	nargo(+bb)	Success
in recursion_js	noir.js(+bb.js)	Coming soon with optimisations

Perhaps the Noir program should be shared, but the tools to use sit outside of that alongside eachother. Eg:

examples/recursion/  (Nargo.toml, src/, etc)
examples/recursion/nargo/ (generate_recursive_proof.sh)
examples/recursion/noir.js/ (package.json ...)