Black all code and add pre-commit hooks

[siddharth-krishna]

6

[ghost]

All CLA requirements met.

[siddharth-krishna]

@samwebster the pre-commit hook should take care of formatting any changed files when you create a commit. (Assuming you use git from a command line, not sure how it works if you interact with git from within VS. I know there's a plugin to format python files using black in VS Code, perhaps there's something similar for VS?)