Revert json v3 logic

[apainintheneck]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

---

This reverts the JSON v3 changes made as a part of #16410 since that approach stalled and the code is not being used for anything. Homebrew/formulae.brew.sh#1704 will need to get merged in first so that we're not relying on any of the files that are being generated here.

CC: @Rylan12 as some of this logic could potentially be useful for the new approach outlined in #19204 and I don't want to disrupt that work if possible.

[MikeMcQuaid]

Thanks @apainintheneck! Looks good when 🟢

[Rylan12]

This all looks good. I guess it's possible that some of the code in tap.rb will end up getting added back, but tbh it's probably just better to have a clean slate and then add things back as they're actually needed. Thanks for checking though!

[apainintheneck]

I was wondering why the tests were running so fast locally. This is my first time doing any extended development on Linux so I didn't realize that the cask tests wouldn't get run. It should be good now as the tests that failed were referencing code that got removed. I'll do a little bit more testing locally and then merge it in.

[apainintheneck]

Ah, it looks like there's some more cleanup necessary of environment variables and filenames.

[apainintheneck]

I tested that the formulae JSON generation is the same minus the unused JSON v3 file but I wasn't able to test the cask JSON generation locally because I'm on Linux and there are some cask loading errors related to the MacOS namespace.