swap most content from #presentation and #none role sections

All of the user reqs and explanation are in the original "presentation" role section of the spec, but we've started emphasizing a preference for the "none" role. To keep in line with that, the content in the "none" and "presentation" sections of the spec should be swapped, along with any required editorial caveats and massaging.

Links

https://w3c.github.io/aria/#none
https://w3c.github.io/aria/#presentation

Does the issue exist in the editors draft

Yes