Adds OgEx support to the standard Phoenix controller render/3 call.
Use it after the application's normal controller setup:
use MyAppWeb, :controller
use OgEx.Controller
Summary
Functions
Installs an OgEx-aware local render/3 in the consuming controller.
The generated function delegates to OgEx.Controller.render/3.
Dispatches a controller render to either Phoenix HTML or an OgEx image.
Without an :og option this delegates directly to
Phoenix.Controller.render/3. With a card, it builds the deterministic card
configuration and selects the response using the signed request parameter.