feat: Add a compile-time hash map type (noir-lang#5543)

# Description

## Problem\*

Resolves noir-lang#5479

## Summary\*

Mostly copied over from our existing hash map with a few changes.
- Uses slices and grows automatically
- Uses `break`

## Additional Context

Like other comptime code, I'm avoiding documenting this until comptime
as a whole is stable

## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[For Experimental Features]** 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.

---------

Co-authored-by: Michael J Klein <[email protected]>

noir_stdlib/src/collections/mod.nr

@@ -1,3 +1,4 @@
 mod vec;
 mod bounded_vec;
 mod map;
+mod umap;