feat: Add HashMap to the stdlib (#4242)

# Description

This PR shall bring HashMap into the `stdlib` of Noir.

## Problem\*

Resolves #4241

## Summary\*

Implementation of `HashMap` with open addressing and quadratic probing
scheme. Since Noir requires knowing loop bounds (and recursive calls) at
compile time, `HashMap` is of fixed capacity and **no** dynamic resize
is accomplished with regard to load factor.

Furthermore, contribution includes implementation of `PedersenHasher` to
be used for now. One can examine potentially better and less heavy
prehash functions.

I tried to conform with best practices of engineering, however since
Noir is in rapid development, there are certain things which may be
optimized in future, both from the code style and performance point of
view.


## Additional Context

I put the `PedersenHasher` among the `poseidon.nr` and `mimc.nr`, so one
can consider moving declaration of other pedersen-related functionality
there, however that would be a breaking change.

## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

noir_stdlib/src/collections.nr

@@ -1,2 +1,3 @@
 mod vec;
 mod bounded_vec;
+mod map;