chore: add commitlint to project

Because the project is pretty strict on what commits are acceptable, it makes sense to lint them locally before they are pushed to a branch.

This MR:

• Adds commitlint to the project.
• Adapts a lefthook configuration example given at: https://github.com/evilmartians/lefthook/blob/master/docs/usage.md#commitlint-example so that commits are checked for anyone using lefthook.
• Updates the Node.js version in .tool-versions to the latest stable.
• Updates .gitlab-ci.yml to use Node.js 18.17.

CC @msedlakjakubowski