[bug 847463] Pull extra top contributors

In case any in the top 10 have been deleted.
Quick fix to avoid overwriting keywords.
[bug 847413] Remove the Help Articles (kb landing) page
Add a customized version of jQuery UI.

The version of jQuery UI has the Sortable and Datepicker features.

We already have jQuery UI, yes, but it is customized to be a subset.
Adding things after the fact is a PITA, so @rdalal suggested I just make
a new bundle that had what I need in it. It gets bundled with
jingo-minify anyways.
[Bug 847874] Plot topic activity over time.

* Shows volume of questions, broken down by topic.
* Pulls data from ES.
* Configurable date range and bucket size.
* Can reorder and hide topics on the graph.