workflow: pin action versions and migrate archived actions

[nozaq]

This PR includes several improvements to the GitHub Actions workflows:

• Replace actions that are no longer maintained with alternatives:
  • Migrate github/licensed-ci to licensee/licensed-ci 😜
  • Migrate gradle/gradle-build-action to gradle/actions/setup-gradle.
  • Migrate from actions-rs/toolchain to using the pre-installed rustup command(reference).
• Pin all external actions to commit hashes, with human-readable version comments.
  • I pined all actions regardless of creators, please let me know if it's intentional to pin actions/* to tags instead of commit hashes. It's also reasonable to do so to reduce dependency management cost if we trust actions organization.

[MikeMcQuaid]

Wonderful, thanks @nozaq!