Add support for HTTP2

Hi,

I'm about to switch my Reagent webapp's frontend server from the JVM to Node.js to take profit from React Server Side Rendering. I'm sincerely considering to use Macchiato as a Clojurish backend server on Nodejs.

I would like to implement some HTTP2 functionalities to push critical assets. Is there a way I can achieve this with Macchiato ? I couldn't find any resources about HTTP2 support.

Thanks for your work and ideas !