Update according to Contributors library guidelines

[thomashoneyman]

This pull request is part of an effort to update and standardize the Contributors libraries according to the Library Guidelines. Specifically, it:

1. Adjusts the files and repository structure according to the repository structure section of the guidelines, which includes standard pr templates, issue templates, CI in GitHub Actions, ensures the project uses Spago, and so on.
2. Updates the README and documentation according to the documentation section of the guidelines. This is a first step towards ensuring Contributors libraries have adequate module documentation, READMEs, a docs directory, and tests (even if just usage examples) in a test directory.
3. Updates labels where relevant to help folks better sift through issues on this library and get started contributing.

This PR is the groundwork for followup efforts to ensure contributor libraries are kept up-to-date, documented, tested, and accessible to users and new contributors.

[thomashoneyman]

These are already understood as global by the configuration.

[thomashoneyman]

The eslint configuration requires indents here; there is no semantic change anywhere in this file.

[JordanMartinez]

I can confirm this fact.

[JordanMartinez]

Should we be removing purescript-psa here?

[thomashoneyman]

Good point; it's not normally included because we normally don't even have a package.json file, and Spago is assumed as a requirement for all libraries. But in this case you're already going to npm i and then use a build command that explicitly relies on psa, so we may as well include it.

[JordanMartinez]

I'm not familar wit eslintrc.json's configuration file, but I'm assuming 2 is a short-hand way of referring to error, correct?

[thomashoneyman]

That's right.