[bug 740013][bug 740431] Upgrade to Django 1.4.3.

* Remove the no longer needed monkeypatch for sha256 password hashes.
* Add a sha256 hasher.
* Update to latest django-authority.
* Minor fixes for test fails.
* Fix fixture related warnings.
* Update password hashes in fixtures to sha256.
* Remove legacy password test as there are none anymore.
[bug 740434] Add special hasher for PASSWORD_DISABLED.
[bug 774855] Update to new django db exception.
[bug 740013] Update admin change_list.html template for 1.4.3.
[bug 821050] Add LOCALE_PATHS settings.
[Bug 821488] Pagination is in wrong place
Fix run_jstests.sh

Add ES_INDEX_PREFIX settings.
[Bug 815670] Add buttons to go to mobile site.

On a small device that is viewing the desktop site, a dismissable banner
will appear at the top of the site, prompting the user to go to the
mobile site. If the user just moved from a mobile page to a non mobile
page, the banner will all the user to go back.

This also adds a middleware that allows us to force a client into either
mobile or desktop view by adding `?mobile=0` or `?mobile=1`, which is
how the "switch to mobile" button works. This is useful for testing.

On large screen devices, these banners are hidden with media queries.

Feedback
[Bug 821705] Don't use viewport units.

Viewport units (vh, vw, vmin, vmax) are not well supported yet, so as
cool as they are, we can't use them for the mobile banners. Switch to
using `pt`, which works pretty good, I just had to think harder.
[bug 822237] Link "Ask a question" to kb for non en-US.
[Bug 816539] Reduce L10n coverage to 30 days.
[bug 822305] Stop mailing admins on django and kitsune exceptions.

Sentry FTW.
[Bug 821274] Generate AoA top contributors stats.

We used to use Mozilla Metrics to measure this. We stopped showing it in
the new design, but re-added it recently. Unfortunatly, it has appears
that Mozilla Metrics is no longer updated.

This commit removes all the old Mozilla Metrics code. It also removes
the code relating to statistics about overall tweet activity, because we
don't currently monitor that (and it wasn't shown anyways).  To replace
the removed code, I added code to generate statistics from the data we
are already collecting about replies that go through the AoA system.

Also made some changes to the tests surrounding these features, and the
format the data is stored in, since the view was previously transforming
the data into this form, so might as well do it in the cron job.

- Deleted some now unused JS.
- These stats now run every hour via cron, instead of six hours.
- Add a migration to update the data in redis.
[bug 822462] Redirect /mobile to /products/mobile
Add title to product landing page for mobile.
[Bug 823049] Add visual cue for blockquoted parts
[bug 822807][Part 1] Add product and topic to question mapping.

Also, rename document_topic and document_product to topic and product.

Tests fail at this point because the view code is not updated in this commit.
[bug 822807][Part 2] Use new mappings.

Switch ES_READ_INDEX to new index.
Add product and topic selection to Advanced Search for questions.
Cleanup usage of |safe for form fields.

They are already safe.
Remove bogus line from tests.