PR: Upgrade, improve and simplify build, CI and pre-commit infrastructure

[CAM-Gerlach]

Pull Request

Pull Request Checklist

• [x] Read and followed this repo's Contributing Guidelines
• [x] Based your PR on the latest version of the correct branch (master or 4.x)
• [x] Checked your writing carefully for correct English spelling, grammar, etc
• [x] Described your changes and the motivation for them below

Description of Changes

This upgrades the various infra to match the improvements on the docs theme, website, etc. I'll have a seperate PR with an updated and improved Contributing Guide (+ README, etc) with various updates along with step by step instructions for contributors even if they're not familiar with Git/GitHub.

• [x] Update pre-commit hooks
• [x] Update lint tool configs
• [x] Fix issues identified by updated hooks/tools/configs
• [x] Split build, lint and check into separate runnable workflows and run on push as well as PR
• [x] Simplify and improve CI workflows based on experience and upgrade deps
• [x] Update gitignore/gitattributes

I'll need to take care merging to master since there will likely be a few conflicts, given this backports and harmonizes a few things to avoid problems in the future, and will wait till the other two PRs are merged to go with this one.

[CAM-Gerlach]

@ccordoba12 Please review. Once PR #246 and PR #296 are in, which should be ASAP (#246 is just waiting on your approval to merge as-is, otherwise I'll just do it, and #296 should be ready, just waiting on a final approve), I can hard-cut over Netlify, the branch protect checks, etc., rebase on the latest 4.x with those changes to ensure everything still passes, merge to 4.x and do the tricky merge to master. (I've marked it as draft to make sure it isn't merged before those)

[CAM-Gerlach]

PR #296 is merged and this is rebased accordingly; this is just waiting on approval here and of PR #246 for me to do the cut-over and then merge.

[CAM-Gerlach]

Thanks @ccordoba12