docs: remove outdated "in production" links

Moat has been bought by Oracle. The advertising subpage redirects to
oracle.com, but pointing at that would be a bit misleading.

No need to keep failing links either.

docs/index.rst

@@ -212,17 +212,12 @@ Here are some companies that use PostgREST in production.
 * `Datrium <https://www.datrium.com>`_
 * `Drip Depot <https://www.dripdepot.com>`_
 * `Image-charts <https://www.image-charts.com>`_
-* `Moat <https://www.oracle.com/advertising/>`_
 * `Netwo <https://www.netwo.io>`_
 * `Nimbus <https://www.nimbusfacility.com/sg/home>`_
   - See how Nimbus uses PostgREST in `Paul Copplestone's blog post <https://paul.copplest.one/blog/nimbus-tech-2019-04.html>`_.
 * `OpenBooking <https://openbooking.ch>`_
 * `Supabase <https://supabase.com>`_
 
-.. Failing links
-  * `eGull <http://www.egull.co>`_
-  * `MotionDynamic - Fast highly dynamic video generation at scale <https://motiondynamic.tech>`_
-
 Testimonials
 ------------