Remove unused imports. Fix typing and indentation

- Typing issues discovered using `mypy'. Fixed manually
- Unused imports discovered and fixed using `autoflake'
- Fix indentation in `org_to_jsonl' manually

src/processor/markdown/markdown_to_jsonl.py

@@ -2,8 +2,6 @@
 
 # Standard Packages
 import json
-import argparse
-import pathlib
 import glob
 import re
 import logging