Follow-up on Repo Enhancement

[Innixma]

Follow-up Items for #1

• [x] #1 docstring consistency :params
• [x] #1 force_to_dense and subset : Add unit tests + docstrings not mentioning private vars
• [x] #11 task_ids and get_datasets -> make tids with problem_types
• [x] #11 subset datasets param -> taskids
• [x] #11 task_ids -> tids, taskids -> tids
• [x] #11 Make tid and tids the public facing args to EvaluationRepository methods instead of dataset_name