Add example app: jokes (Js.Json.t version)

[drewschrauf]

This is a follow-up to #20

It addresses a few of the points raised there but a couple of the solutions are controversial so I'm raising it as a separate PR. In particular:

• It doesn't try and solve the loader/action type safety, opting to instead treat everything as Js.Json.t
• It uses decco to make dealing with Js.Json.t easier
• It uses another patch-package diff to allow the user to customise the server-only component regex
• It has a few partially-implemented Remix bindings

I'm keen to see if you think this is moving in the correct direction or if some of these changes are just too naughty.