Common TSV Handling

[BatuhanSA]

We should define a common and consistent approach for generating TSV output so the format is uniform everywhere.

[eriq-augustine]

We may want to think bigger with this issue.
Instead of just TSV handling, maybe we should consider basic output formatting for a wider range of types.

In the LMS toolkit, we do something similar with the base types:
https://github.com/edulinq/lms-toolkit/blob/main/lms/model/base.py#L233
Any class that extends the base type gets output formatting in text (human readable), table (tsv), and JSON for free.
The base type here extends the DictConverter from this project:
https://github.com/edulinq/python-utils/blob/main/edq/util/json.py#L16
So maybe, we can pull this functionality back to the dict converter.