Add a Products View

Includes updates urls, a new form, template and a class based view.
It needs some CSS love, but otherwise works.
I'm pretty sure you can do this and it'd be simpler:

```
from django.forms import ModelForm

from fjord.feedback.models import Product

...

class ProductsForm(forms.Form):
    class Meta:
        model = Product
        fields = [`enabled`, 'display_name', `db_name`, 'slug', `on_dashboard`, `notes`]
```

Django will then infer the form and its validation rules from the existing model.