Add a Products View

Includes updates urls, a new form, template and a class based view.
It needs some CSS love, but otherwise works.
Nit: We sort imports in the following way: Python stdlib imports, followed by django imports, followed by third-party imports, followed by fjord imports. Each of those groups has a blank line after them.

So here, we'd do:

```
from django.conf.urls import patterns, url
from django.contrib.auth.decorators import login_required

from fjord.analytics.views import ProductsUpdateView
```