Add five sample credible_content seed items

[slifty]

These were manually "scraped" but will hopefully reflect the same kind of format that will come from the scraper once it is finished. Specifically, it is going to mirror the content on the fact checking sites, including paragraph tags, links, spans, etc.

If we ultimately decide to try to strip those things we will come back and edit this seed list

[slifty]

@knowtheory I have to run out for a moment but please feel free to merge this so you aren't blocked (assuming it all passes basic muster)

[knowtheory]

lgtm 👍