(DNM) bug 926316: Raw search tool for macros, classes, attributes

Okay, here's my second try. It might not be ready for a merge yet, but could use some eyes.

This adds new elasticsearch indexes and extraction code for KumaScript macros, CSS class names, and HTML attributes.

After that, I add a very rough and crude page with a form to search on those indexes. For bonus points, there's a JSON view, which can be a data source to KumaScript macros.