Save history of holdings_status table for debugging

Store all changes to holdings_status table in the database, to allow viewing history of changes for loading status.

Technical details:
Create table holdings_status_history with version or updated_date column.
Add a database trigger to save status on update to holdings_status table. Make sure that trigger runs after existing triggers, so that correct value is saved to history.
Delete rows that are older than certain amount of days(30 days) during call to POST /loadHoldings endpoint.

Acceptance Criteria
History data should be stored in the same json form as the status in holdings_status.
History should be updated every time status is changed.
History data should be cleaned during every refresh(clean records older than a month) to avoid using too much database space.
Add unit tests