fix linting errors on utils package

[nathonfowlie]

• Fixed linting issues found by flake8, pylint and black in the utils package.
• Fixed some missing type hints, but didn't resolve all issues found by mypy.

refs:

• relates to https://github.com/alexlaverty/python-reddit-youtube-bot/issues/17

[nathonfowlie]

merge commit hell because main was getting updated faster than I could do another rebase :P