Add high-scores exercise

[ErikSchierboom]

No description provided.

[tasxatzial]

This is one of the exercises where the terminology from canonical data conflicts with Clojure terminology. There's an open issue about it (no discussion, though) because there have complaints that it's confusing. See #671

To sum up, scores_test_1 and personal-top-three_test_1 both use the word "list", but the actual test uses vectors. One option is to change their descriptions to refer to vectors. Another option is to do nothing. But in any case, I'm always adding an append file because the description also uses lists.
This one here can be copied as is:https://github.com/exercism/clojure/blob/main/exercises/practice/sublist/.docs/instructions.append.md

[ErikSchierboom]

@tasxatzial I've converted the template and tests to use a list