Fix loading

As for many client side rendering patterns (turbo-links, pjax, etc.), you can't rely on the `DOMContentLoaded` event to detect when the DOM is ready to be manipulated. Instead make prismic trigger its own `'prismic:rendered'` event. 

Fix the qubico script to bind to this event instead.

> Note: we will probably have the same problem with releases rendering, as the rendering is done in-place (without page reloading), and I think that many client side templates, including this one, won't support properly this kind of reloading.