Add before/after content and truncation behavior

[jkeck]

The "truncation" renders the full snippet (before/after) in the panel by itself w/ a link that will go back to the Annotation list.

(Edit by @ggeisler below with some details)
We'll have to pick some character or word limit to trigger truncation. This will probably be easy to adjust so as a starting point I'll suggest 200 characters, which would produce something like this result:

When the user selects the "more ..." link, that should take them to the detail result view panel described in #2688.

[cbeer]

I'm going to take the more link behavior over to #2688.