ci: Add GitHub Actions build-lint-test workflow

[legobeat]

Template from metamask-module-template

This runs on Nodejs versions 12 (currently supported version) and 14.

Note that tests fail on Node.js versions >= 12. fail-fast is temporarily set to run the full matrix regardless. This is intended to assist in unbreaking it and can be removed once resolved.

This does not:

• save HAR logs like the circleci job (do we want this?)
• remove circleci (will add here if desired by reviewers)

[legobeat]

Sample run: https://github.com/legobeat/eth-token-tracker/actions/runs/3645421931

Initial error (this goes further but one step at a time) addressed in #82

[mcmire]

~I see you've run these actions in a fork. It doesn't seem like the new actions you've added are getting run in this PR. I wonder if we have to enable actions on this repo in order to do this.~ Edit: Actions are now enabled, so you should be able to run these here.

[mcmire]

With regard to:

• save HAR logs like the circleci job (do we want this?)
• remove circleci (will add here if desired by reviewers)

I think we can safely remove these. I don't recall needing to access old logs in CircleCI, and for GitHub Actions, GitHub stores logs already.

[mcmire]

I'll look into why these tests are failing on Node 12 shortly.