refactor: tidied existing mocha test scripts in package.json and added a test-ts script

[RohanTalip]

Description of change

mocha allows for configurations to be put into files. See https://github.com/mochajs/mocha/tree/master/example/config and https://mochajs.org/#configuring-mocha-nodejs .

This allows the test and test-fast scripts in the package.json file to be more concise.

I find YAML to be more concise for mocha configuration files than JSON files, but also allow for comments. I added a .mocharc-compiled.yaml file for the test and test-fast scripts, and I also added a .mocharc.yaml file for a new test-ts script that uses ts-node (to run the tests without needing to compile/transpile them first), and which will also be used by default when running npx mocha path/to/test.ts.

Most tests are passing locally when run via test-ts path/to/test.ts or npx mocha path/to/test.ts. I fixed some imports/requires in some tests but there are still a few that are failing locally, on my Mac.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run format to apply prettier formatting
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000
• There are new or updated unit tests validating the change
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md