Show 6 random clients on homepage

Showing all of the client logos adds a considerable amount to the page weight of the page. This change shows 6 random clients. It will be re-generated each time the page is deployed, which might be OK for now, although we could add timed pipeline to keep this fresh/fair.

What do folks think? This certainly makes the page lighter, but there's now no central big list of clients. We could add one I guess?