Host the static content at colaboratory.jupyter.org

[fperez]

Create a site with all the same static content that the chrome app needs, so that Drive-hosted notebooks can be rendered without users having to install anything other than registering colaboratory.jupyter.org as a known Drive app.

[fperez]

Domain now exists along with repo being served via gh-pages. There may be more fixes to do, but we can close this issue now and tackle any specific new ones in that repo.