Add context processor for settings variables

This allows for usage of settings variables in templates, e.g

```
{% if settings.USE_ANALYTICS %}
<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id={{ settings.GOOGLE_TAG_MANAGER_ID }}" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->
{% endif %}
```

{{cookiecutter.project_slug}}/config/settings/base.py

@@ -187,6 +187,7 @@ TEMPLATES = [
                 "django.template.context_processors.static",
                 "django.template.context_processors.tz",
                 "django.contrib.messages.context_processors.messages",
+                "{{ cookiecutter.project_slug }}.utils.context_processors.settings_context",
             ],
         },
     }

{{cookiecutter.project_slug}}/{{cookiecutter.project_slug}}/utils/context_processors.py

@@ -0,0 +1,5 @@
+from django.conf import settings
+
+
+def settings_context(_request):
+    return {"settings": settings}