Subjects / Coverage: Make edit forms, faceted search and virtual navigation use the same vocabularies

For instance, on the edit form of documents, level 1 of Coverage metadata displays:

• [...]
• Australia / Oceania
• North America
• South America

(Virtual navigation tab displays the same list). Both use the Coverage vocabulary.

On the Coverage list of faceted search, it displays:

• [...]
• North America
• Oceania
• South America

This list uses the I10ntopics vocabulary.

The same is true for Topics, Subtopics, I10ntopics vocabularies.

All lists should use the same vocabularies, because users won't probably edit all vocabularies if they want to customize metadata values, and if they do, it's painful and boring.