[Feature] Add SEC As Provider To equity.ownership.insider_trading

[deeleeramone]

1. Why?:

   • Expand the coverage of data directly from the SEC.

2. What?:

   • Adds sec as a provider to, obb.equity.ownership

3. Impact:

   • Download historical filings is a relatively expensive I/O transaction to the SEC, this persists downloaded forms permanently as a parsed, compressed, SQL database in the user_cache_directory.
   • Using the cache can be disabled with use_cache=False
   • A narrow width between start/end dates should be used, some companies have few, or no, insider transactions, while others have hundreds every year - CRM. Approach as a drinking fountain vs. a fire hose.
   • For SEC, default start date is 120 days ago, if not supplied.

4. Testing Done:

   • Unit/integration.

A message will display how many cached vs. uncached items there are for the current request.

A note urges caution with requesting wide date ranges.