Eng 808

[egh]

JIRA issue: https://jira.plos.org/jira/browse/ENG-808

What this PR does:

• I created a layout in the previous ticket, but I forgot to use it in some of the exports. This fixes that.
• In the answer export, and type of card content can have children. We were only exporting the children for display-children type of content; I fixed it to always display children
• Added [No response] when there is no answer

• Renamed generic_answers.html.erb to review.html.erb because that is the only place it is used

  How to test

• bundle exec rake export:manuscript_zip[pbio.2007093]

If you don't have a local db dump and access to the S3 bucket, ping me & we can figure it out.

Code Review Tasks:

Reviewer tasks (these should be checked or somehow noted before passing on to PO):

• [ ] I read through the JIRA ticket's AC before doing the rest of the review
• [ ] I ran the code (in the review environment or locally). I agree the running code fulfills the Acceptance Criteria as stated on the JIRA ticket
• [ ] I read the code; it looks good
• [ ] I have found the tests to be sufficient for both positive and negative test cases