Geo: Enable FDW by default
While working on #3173 (closed), I realized that we might want to enable FDW by default now. Right now it looks like Geo sets up all the required tables for FDW, but it doesn't actually turn it on for Rails. That disconnect is a bit confusing: either we use FDW or we don't.
Given that it's been running on GRPD nodes for a while now and showing benefit for large installations, I suggest we enable it.