Feature/rosie metadata mappings

Per @ckassel's comments in [PivotalTracker](https://www.pivotaltracker.com/n/projects/1025368/stories/73472536), this PR:

- uses the handle (which is now available in Sorl) as the URL for the Rosie interviews
- removes language, since the Drupal install that runs the Rosie site doesn't support it
- uses the handle as the citation, a la the [FDA](http://git.io/3KfOGg)
- adds examples to the RosieTheRiveterReader spec