CI pipeline improvements

[nscuro]

• Only build against Temurin, drop Zulu
• Build against Java 8, 11, 17, and 21, instead of just 8
• Pin 3rd party actions to their digest
• Drop permissions on workflow-level, define them on job-level
• Update JamesIves/github-pages-deploy-action to the latest version
• Update release-drafter/release-drafter to the latest version
• Run the Maven CI workflow only for pushes to, or pull request into, master. Previously we had duplicate runs for PRs.
• Reduce build output noise by disabling Maven's transfer progress logs
• Record test coverage with JaCoCo
• Publish coverage reports to Codacy
  • Because we build against multiple Java versions, we'll upload only the report generated from the latest Java build