Cleanup GitHub Actions workflows

[danielrozenberg]

• Remove jobs that have been manually disabled or were never configured correctly
• Remove reference to the non-existent ACT env variable
• Replace npm install with npm ci (CI jobs should not regenerate package-lock.json)
• Renamed *.yml to *.yaml to keep consistent :)
• Update NodeJS version from 14 to lts (reverted for now, will deal with this later)
• Remove the custom call to action/cache and replace with the built-in caching mechanism in action/setup-node
• Add workflow-dispatch: trigger (manual trigger) to all remaining workflows, so we can trigger them on PRs that we want to double-check, even if the PR itself doesn't trigger those workflows automatically

[powerivq]

Thanks! Don't know if latest LTS has been tested successfully though? I think some won't work on latest.

[danielrozenberg]

Thanks! Don't know if latest LTS has been tested successfully though? I think some won't work on latest.

Fair enough, I don't know why I assumed for one second that this would Just Work with a simple version bump... Let me double-check this on my fork 😅

[danielrozenberg]

Invalidating the approval so I won't accidentally merge this

[danielrozenberg]

Let's revert the lts change in this PR, I'll deal with that specific change in a separate PR. Re-approval required :)