* [WIP] pull OHLCV records from Crypto Compare
* lint
* refactor to pull logic out of script and into modules
* add entity test for ohlcv_external entity
* implement rate limit and chronological backfill for ohlcv
* add unit tests; cleanup variable names
* Fetch OHLCV pairs params from events table
* better method names
* fix outdated test
* lint
* Clean up after review
* oops
* fix failing test
* better filtering of most recent records
* fix bug when generating pairs
* fix default earliest backfill date
* fix bug with retrieving backfill time
* prettier
