add draft of pre-loaded apps terms and conditions (bug 907418)

[original document](https://bugzilla.mozilla.org/attachment.cgi?id=833223)

Added a Markdown file to https://github.com/mozilla/marketplace-docs/pull/3 but don't know if that's a good place to put it. It's only there in case legal wants to update the copy, but then we'll have to bump ```media/docs/preload-apps-terms/``` whenever there's new translations/updates.

Converted the markdown to HTML and added it as a doc here. Maybe a ```trans``` would be better since it's mostly a big table? Open to input.

![screen shot 2013-12-03 at 6 03 08 pm](https://f.cloud.github.com/assets/674727/1669998/70637f06-5c88-11e3-855e-9b8e6c9084ba.png)