Bug/issue 604 fix json fetch handling

[thescientist13]

resolves #604

Summary of Changes

1. For now, have to add an "internal" API to capture originalUrl as a header to play nicely with make resource resolving more graceful and fallback to original ctx.url #599 wherein if we have query strings in URLs against the filesystem, then things will break, so need to preserve query params another way
2. Adapted plugin-standard-json accordingly, and then the ?type=json logic of this will get extracted out into have a plugin for being able to import JSON using ESM #516

As with anything non standard, this is no "right way" per se to solve this. So far the best hint I can come up with is this

import json from '/package.json?type=json';

Which takes some influence from a potential standard called import assertions
https://github.com/tc39/proposal-import-assertions

TODO

1. Add some tests
2. Setup a discussion to review best way forward for things like have a plugin for being able to import JSON using ESM #516 and other assets like CSS and potentially images - Using `import` for non JavaScript modules #606
3. Clean up test code