SEC Filings loader bug fixes

[Athe-kunal]

Description

The previous SEC Filings loader that was developed by me had some major bugs as the SEC website changed last year. In this modification, I have fixed the bugs, returned the text data in document format compatible with llama index, and added extra metadata to the texts like the filling and reporting date

Fixes # (issue)

Type of Change

Please delete options that are not relevant.

• [ ] Bug fix
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• [ ] I stared at the code and made sure it makes sense

• [ ] I tested with my local environment with all the dependencies and it worked

  Suggested Checklist:

• [ ] I have added a library.json file if a new loader/tool was added

• [ ] I have performed a self-review of my own code

• [ ] I have commented my code, particularly in hard-to-understand areas

• [ ] I have made corresponding changes to the documentation

• [ ] My changes generate no new warnings

• [ ] I have added tests that prove my fix is effective or that my feature works

• [ ] New and existing unit tests pass locally with my changes

• [ ] I ran make format; make lint to appease the lint gods

[Athe-kunal]

@jerryjliu Can you merge it?