Use partials to render module pages

Hey @redmunds, this is some initial work for #60, applying the partials idea to the module pages.

The goals of this are:
- Prevent `module.html` to become a gigantic unreadable beast like it already was :)
- Group common patterns in templates so we can change them all at once and avoid find/replace copy/paste
- Make it easy to configure how specific parts of a page render
- Make it easy to render only parts of that page. This should help the Brackets-apify extension to render only the module part of the page, avoiding the navbar and filelist.

There's still plenty to do here, but since it's a lot of work, I wanted to start pushing it out. What do you think?