Clean up test folder

[HEdingfield]

It would be nice to standardize the file names and clean up the test folder. I like the format date-location-office. Maybe we could consistently prepend cvr_* and config_* to those.

There also might be some test files in there that aren't needed anymore or, if they are, could also have more consistent names (e.g. "minimum-threshold-test-cvr.xlsx", "test_continue_tabulation_config.json", etc.).