test: new GitHub Actions for front, back, Docker; increase PyWorkflow coverage to 83%

[reelmatt]

There are now three GitHub Actions triggered on each push/PR: 1) test_backend.yml: Was the exiting GitHub Action. Builds/runs back-end server. Runs PyWorkflow unit tests and Postman API tests. 2) test_frontend.yml: Builds the front-end server, runs the Jest tests. 3) test_docker.yml: Builds and runs both Docker containers with docker-compose.

The front-end Action is currently failing. @cesaragv has #88 open to increase coverage and is working on the fix for the React hooks.

Also included in this PR is more PyWorkflow unit tests. Coverage had actually decreased to ~70% (mostly due to the addition of new Nodes); now back up to 83%.

[reddigari]

Any way to retain the Docker images as artifacts? I see there's a section for them but they aren't there. Also no way to view the log of the image builds?

[reelmatt]

Actions do support artifacts (and also caching which seems similar but different). I agree those would be good to implement, I just hadn't spent a lot of time on them.

Re: logs, those should be available in the Action output. They should be in there from the first commit this PR, but I did separate out some steps at one point. If you expand "Build docker container" you should see something like:

I think that's what you're talking about?