FEAT: Content updates to FAQs: submission guidance

Implemented content upates for FAQ. Added new pages for readme and
filetype guidance for submitters.
additional FAQ page content updates
adjustment to numbered list type in FAQ sublist
set list numeric style directly for FAQ page
additional tweaks to faq, filetypes, and readme static pages

https://dev.datadryad.org/pages/faq#depositing

What kinds of data does Dryad accept?
 - hyperlinked text: change from "View" to "additional guidance"

 (sorry for not specifying this. the best practice rule i've learned is that the linked text should
 describe what's being linked to, versus something like "view" or "click here.")

 In what file format(s) should I submit my data?
  - hyperlinked text: change from "preservation-friendly file formats" to "additional guidance"
   - add "of" before "preservation-friendly file formats"

   How can I make my data submission as accessible and reusable as possible?
    - hyperlinked text: change to "additional guidance" and "ReadMe file"

    What should I prepare before submission?
     - hyperlinked text: change from "View" to "additional guidance"

     How do I write a ReadMe file?
      - hyperlinked text: change from "View" to "additional guidance"

      How much does it cost?
       - can the ordered list be indented, and a line break added after it?

       https://dev.datadryad.org/pages/filetypes

       Looks good, h1 is fine. Can we add a line break before the last sentence,
       "For comments/questions..."?

       https://dev.datadryad.org/pages/readme

       Looks good, h1 is fine. Can we add a line breaks after the unordered lists? (Before "We
       recommend..." and "If text formatting..." This is a pet peeve of mine, and it may be a CSS
       thing. Not a huge deal if it doesn't happen.
fixed additional link text
Merge pull request #694 from rnathanday/trello-69

Trello-69: FEAT: Content updates to FAQs: submission guidance