Snowflake bulk loader doesn't format dates and timestamps correctly

The COPY INTO command only accepts a very specific format for Dates/Timestamps.

See: https://docs.snowflake.com/en/sql-reference/parameters.html#label-timestamp-output-format

It would as such be better to just format the dates in the temporary files to that format (For reference: yyyy-MM-dd HH:mm:ss.SSS)