support for translations

[seanno]

This could get really hard but if patient summaries in particular move between regions, it'd be great to help folks interpret them. Browser-supplied translation is ok as a fallback but would be nice if we could:

1. At least leverage multi-lingual data if it exists in the bundles. Research to do on how this gets represented.
2. Use language-aware terminology lookups
3. Localize text in the viewer itself (vs just the bundle)
4. Other features as necessary

Just a placeholder for now --- research to do.