#681 - Update raw save-to-disk

[kdetry]

Fixes #681

Changes proposed in this PR:

• CSV Data Store class is created
• implemented to the table.py
• tests are updated

PS: I didn't touch the OHLCV process because it looks like it has its own system and works properly

DoD

Load from + Write to CSVs...Just append

• Please create a new function called append
• After fetching new data, users will append data to a table.
• Inside of append(), call a new function called append_to_csv. We just want to append a few rows at at time to a csv with as little latency as possible.
• Inside of append(), call a new function called append_to_duckdb. Comment this out. Address this in the next ticket.

[idiom-bytes]

This PR contains fixes & updates that are required for other PRs to move forward.

If your needs for CSVDataStore won't change @kdetry, then perhaps use this. Otherwise, I recommend you cherry-picking changes from as needed to continue with the other PRs and get the DuckDB Integration PR working.

I believe we should update CSVDataStore and have it "clean/simple".
There are updates required to clean up stuff in here that is part of "DuckDB Integration" PR.

[kdetry]

We will continue on the following PR

#734