Add task-test metadata v2

[miridius]

This PR is an updated version of #434

Sorry for creating a new PR, but I don't have permission to push my changes directly to the existing branch and couldn't see another way.

What I've done:

1. Rebased the existing #434 branch on top of main (since it was quite old) and resolved the merge conflicts
2. Updated the metadata format to match what the test runner will support once exercism/clojure-test-runner#43 is merged
3. Added task metadata to the tests for the only 2 exercises that have task numbers but didn't have metadata yet. I think both are still WIP exercises but doesn't hurt to add the metadata anyway