chore: add pre-commit configuration file, run ruff-isort

[agriyakhetarpal]

Description

Continuing from #633, this PR adds support for the pre-commit via its configuration file, which works with https://pre-commit.ci. More information to help make review(s) for this PR easier:

• I have suppressed all failing rules to get pre-commit passing in 68e3dda, so that we can fix them all later.
• At most, the style changes in this PR come from 0f7bce4, where the imports have been tidied up and sorted using the ruff check . --select I --fix && ruff format . command.
• The pre-commit config configuration file was added in 5da6308. Please let me know if we need to add any more hooks! This is the only relevant commit, the other commits are just for stylistic changes because I didn't want to let CI fail here.

Additionally, to automatically enable pre-commit as a Git hook locally, type:

pip install pre-commit
pre-commit install

and subsequently, it would not allow creating commits that fail the style rules we have set in pyproject.toml or those in .pre-commit-config.yaml.

[fjosw]

Hi @agriyakhetarpal , looks good to me, thanks for tidying the code base up! For now, the pre-commit hooks are only locally executed (if configured by the user) and not validated in a GitHub actions workflow, correct?

[agriyakhetarpal]

Yes, you are correct. They are just locally executed for now. I opened an issue as a reminder for us to do that: #637. We could add it here, but my thoughts were that having a smaller diff would be nicer. Thanks for the review!