Parallelize tests run on GitHub Actions

[lread]

In addition to being broken down by OS, tests are now also broken down by
major type (ide, api, unit) and browser (chrome, firefox, edge, safari)
for ide and api tests.

Observations:

• can now more readily see what we are testing by the job breakdown in
  GitHub Actions UI
• nice to have an overall shorter test run. I'm seeing ~8m to completion instead
  of the former ~15m
• faster feedback for what is passing/failing
• some windows tests might be a bit flaky, but good to know, so that we can
  address, right?
• very nice to be able to rerun a single failed job, for example, if
  unit windows has failed, I can rerun it alone via the GitHub UI.

The current tests only invoke chrome and firefox for ide testing, so
I've stuck with that. Api testing matches current browser defaults.

I'm liking keeping the brunt of the work out of yaml and in babashka
tasks. The yaml has a setup job which:

• brings down Clojure deps to be cached
• learns what tests should be run via
  bb script/test.clj matrix-for-ci --format=json

The build task then:

• runs the tests found by the setup task. Test runs on ubuntu include
  launching a virtual display (necessary for GitHub Actions)

Of note:

• New custom test reporting spits out the browser (for api and ide
  tests) and the name of the test being run. This feedback is nice
  especially for api tests which are long-running. It also helps to
  validate we are testing what we think we are testing.
• Added ^:unit metadata to unit test namespaces
• I noticed GitHub Actions was passing failing Windows tests and learned
  how powershell needs a little help in propagating return codes.
• Because browser sets are different for api and ide tests, I left
  the existing ETAOIN_TEST_DRIVERS env var for api tests and introduced
  ETAOIN_IDE_TEST_DRIVERS for ide tests.
• Brought in some more scripting helpers from other projects, refactored
  existing bb tools-versions script accordingly

Closes #420

[borkdude]

Huge improvement!

[lread]

Thanks, @borkdude! I especially enjoyed enumerating the matrix jobs to run on GitHub Actions from a babashka task.

[borkdude]

@lread Haha, wow, I missed that, nice.