feat: add nargo compile --watch command (#4464)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR creates the outline of a `watch` command to be built on in
subsequent PRs.

Currently this just watches the full workspace directory and on any
change to a `.nr` file, will recompile the workspace/package and display
any errors/warnings.

## Additional Context



## Documentation\*

Check one:
- [] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[Exceptional Case]** Documentation to be submitted in a separate
PR.
Will be documented when feature is public.
# 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.