Use views to output aggregator items

Let's see what breaks.

I made a couple of bonus edits to the feed template file. I noticed that they were needed while I was trying to understand how to make the feed title not be rendered.

The last submitted patch, 25: 2680527-25.patch, failed testing. View results →

The failures were due to post-migration entity counts that needed to be updated since I added three new entities.

I'm setting this back to active because there's more work to be done on it. An upgrade path needs to be written. We need to decide whether the Items component of the Feed view should be deprecated. I'd say "yes." I looked at what the Taxonomy module does for Terms to try and find a best practice. It doesn't appear to have a component for displaying referenced entities, deferring that responsibility to Views. Feeds and their Items are a slightly different scenario, but I'd still prefer to do all query building with Views.

Exciting to see this moving 🎉

Rerolled 27.