Semantic annotation primer needs a FAQ for 'what is a "good" triple-subject?'

[mobb]

possibly restate the FAQ. In the primer, there were notes about what made a proper triple subject that were removed to simplify the main body. They need to be summarized as an FAQ, and then linked back. Removed text is below.

[robyngit]

@vchendrix if ESS-Dive has requirements other than those listed here, it would be great to know about those!