Centralize conf

Goals:
* There's only one conf file to change
* It seems we forgot the port in the html files. I added it. (correct me if I was wrong)

Next steps would be:
* Give the ability to have a `config.local.js` which could override the default `config.js` and be gitignored
* Let "http://" be in the config file (I've let it outside because it seems to mess things up because of slashes which are replaced by their ascii code. (probable just a mustache flag, I just didn't had the time to look into it yet)