Create spike for Cypress E2E testing

[patcon]

Resolves #1762

• install cypress in frontend/
• add scaffold files
• add simple starter tests
  • footer
  • static pages (ToS and privacy)
  • language selection page
• increase quality of generated video artefacts so that debugging is easier
• fixed outdated editorconfig file
• wrote docs for cypress testing and custom commands
• add github action workflow
  • docker layer caching preserved between workflows, so 3s rather than 2min
    • layers cached between workflows: docker smoke tests, and past runs of this
  • cancel other versions of workflow that are mid-run (concurrency settings), to not waste build minutes
  • save screenshots as artifacts on failure
  • save video screencasts of tests as artifacts (see summary page to download, great for debugging)
• add reporter to print Cypress logs for failed tests (that would normally show in Cypress console) to CI terminal logs
  • https://github.com/archfz/cypress-terminal-report
• enable junit xml reporter for tests and report via github actions wont-do
  • https://github.com/EnricoMi/publish-unit-test-result-action
  • https://docs.cypress.io/guides/tooling/reporters#Reporter-Options
  • https://github.com/bhovhannes/junit-report-merger
• enable multi-reporter to still get output into terminal logs
  • https://github.com/you54f/cypress-multi-reporters

[patcon]

Yay! It works!

It takes quite some time to run setup.sh, but the docker build went from 1min to 3s with the layer caching, so that's a good sign that this will be real quick once we have the app actually building in docker :)

cc: @petertgiles

[patcon]

Going to back out of the reporting goal, as it's a little fraught.

Examples:

• dorny's test-reporter using java-junit reporter: https://github.com/patcon/gc-digital-talent/runs/6186727684
• using another reporter action
  • https://github.com/patcon/gc-digital-talent/pull/288/checks?check_run_id=6186621165
  • [TEST] 1762 cypress spike patcon/gc-digital-talent#270 (comment)

both reporters took awhile to debug because the check results are showing up under "Bundlewatch" check for some reason, which is perhaps due to "Bundlewatch" action doing something non-standard.

Also, there's some confusing work to make GitHub check reports work for forks:
https://github.com/EnricoMi/publish-unit-test-result-action/tree/v1.20#support-fork-repositories-and-dependabot-branches

Also, cypress has an issue with mocha reporters can't have their output locations configured right now:
cypress-io/cypress#18014

tl;dr - too many rabbit holes here!

[patcon]

@petertgiles the interface won't see to let me, but I'm undesignating you as reviewer! [EDIT: figured it out 🙃 ] (I am too quick to tag you, and it's a bad habit 🙂 )

@esizer @yonikid15 you seem like you'd get a kick out of e2e tests. Care to review when you get a sec? :)

[esizer]

Looks great! Just noticed a small change to the footer test descriptions

[patcon]

Added an line comment: Some of the footer checks are skipped until this bug is fixed
#2565

[esizer]

Sweet! 🍭