Restructure zip export for #2136 use original filename for #2811

[benwbrum]

[saracarl]

This configuration: Has the following issues:

1. We include folders for each work (the "old" way), and they appeared first in my zip file, which confused me, since they weren't what I asked for and they were empty. We need to remove the work-folders if you request format level exports.
2. We need a readme for type of exports. I asked for work level html exports, organized by format. I got 3!
3. The html_full export looks correct -- it has versions with contributors & dates, linked subjects, and subject articles.
4. The html_text export is transcripts, links subjects, and has subject articles. Seems reasonable, but I'm not sure what was intended.
5. The html_transcript export does not include contributors/versions or subject articles, but does link the subjects (the links go to an anchor that doesn't exist in this file). This is wrong.

[saracarl]

We need to make sure this doesn't close issue #2811 because there are a number of separate changes there that aren't part of this PR.

[saracarl]

passing tests. the pdf export metadata has "in scope: true" listed, even though I didn't mess with the "additional metadata". That seems like a bug, but outside of this. Opening a new issue.

[benwbrum]

Passing tests locally. The directory restructuring has been fixed.