Remove xx/Pirate from AAQ_LANGUAGES.
Renamed stats to metrics for consistency with KB dashboards.
[bug 907748] Add questions metrics to metrics page.
Edit button for question details
[bug 897058] AAQ flow sign in/register with Persona
[bug 905118] Redirect correctly on sign in with Persona
[bug 897985] Persona for mobile
[bug 909660] Track read after 5 seconds on landing page.
[bug 903829] Show redirects in /documents separately
[bug 907053] Remove hot topics landing page
[Bug 906992] Set up multiple ES index framework.

Now settings.py can contain multiple indexes in ES_INDEXES and/or
ES_WRITE_INDEXES, and models can choose which kind of index to use. The
admin and management commands have been updated, and I updated search
and other parts of the site that use elastic to account for multiple
indexes, where needed.