[bug 1079413] Make certain contributor articles collapsible.

This is for a test, so I just put the articles list in the config. If this catches on, we'll want it to be in a db column or some special markup inside each article.

The actual code that does the collapsing already existed, I just tweaked it so it wouldn't default the first section to open.

r?
Oh, I just did this `import kitsune.wiki as config` but you are right. We have been using config.py for this stuff. Let me move it there.