Make evaluation references more open

[jandrieu]

Currently, the Rubric reads as if all of the examples form a single evaluation. However, that is already out of date, as @dhh1128 has also added several example evaluations on his own judgment.

We need to add @dhh1128 to the evaluator's list, add an entry in a evaluation sources list, and add citations to the examples from that evaluation.

This should also make it easier for new PRs to come in from other evaluators, without losing the origin of said evaluations.