Update and lint GitHub Action workflows

[MakisH]

This PR:

• Adds a pre-commit hook to lint GitHub Actions, using https://github.com/rhysd/actionlint, and fixes all linting issues
• Bumps all GitHub Actions to their latest versions
• Removes the unused check-links.yml workflow
• Specifies the timezone to the scheduled workflows, for clarity
• Potentially fixes an issue with the system tests failing at the upload-artifact step (failing job).