🎨🚨 Add pre-commit and Pylint

[mayankpatibandla]

Summary:

Adds pre-commit to run some hooks that must pass before a commit is allowed. Some basic errors regarding whitespace and unused variables have been fixed. Also adds Pylint to GitHub actions.

Motivation:

The goal is to enforce a more consistent coding style and fix linting issues. Currently most errors have been disabled, but we will need to enable some of them later to comply to a chosen standard.

References (optional):

#300

Test Plan:

• [x] To set up pre-commit, run pip install pre-commit if you don't already have it, and then run pre-commit install in the project directory. Pre-commit hooks should now run automatically every time a new commit is made.
• [x] Ensure that pre-commit run --all-files passes for all files in the project.
• [x] Ensure that the GitHub action is successful

[ayushuk]

@mayankpatibandla Can you solve the conflicts in the meantime?

[mayankpatibandla]

Conflicts have been resolved

[ayushuk]

Lets wait to merge this after 3.5.1 since we want to get that out quickly and then when everything is stable again we can merge this and start enforcing it.