Use ETT table of contents

[elichad]

Bert: The theme itself does come with a table of contents that is automatically generated so I think you can minimize the amount lines in the markdown by not including it as part of the page content. It also renders on the side (and looks better imo) which means that people will quicker find the content instead of heaving to scroll.

Eli: we have overridden the TOC creation in head.html but still use the ETT file assets/js/toc.js to create the TOC. Normally it would be in page.html