Closes #3525

This PR updates the conversion of relative import paths to absolute import paths, to be used in Codesandbox where the relative files aren't present.

Previously:

• mdx-hast-to-jsx would identify any relative imports in example code (import Something from '../Something.js'), parse out the name of the imported item, and build a map matching this relative imported item to the absolute import path for it
  • { Something: '@patternfly/some-package/Something.js' }
  • This is referenced in codesandbox.js to use simple string replacement to swap out the relative path with the absolute path in the example code before sending to Codesandbox example
  • Code had bugs and added extra complexity by parsing out imported item names from relative import path, when we already have relative & absolute paths which is all we really need

Now:

• mdx-hast-to-jsx maps the relative import path (not the name of the imported item) directly to the absolute import path
  • { '../../Something.js': '@patternfly/some-package/Something.js' }
  • This also resolve the issue of destructuring relative imports including multiple items (ex: import { rows, columns } from '../../Data.js') - what is being imported doesn't really matter, we're just concerned with finding the relative file where it's coming from and getting the absolute path to that file.