title: How to load a django contrib app without modifying directly the templates of the project
body: <p>I have built a django app, which when enabled (from the settings.py), can be accessed by the main menu of the project. 
  In order to check if the app is enabled, I use this snippet in one of the templates:</p>
  
  <pre><code>{% if 'my_project.contrib.edit_app' in INSTALLED_APPS %}
                  &lt;a class="btn btn-danger btn-block btn-xs" href="{% url "display_data" resource.service_typename %}"&gt;{% trans "Edit App" %}&lt;/a&gt;
  {% elif 'my_project.contrib.edit_data' not in INSTALLED_APPS %}
              &lt;a class="btn btn-default btn-block btn-xs" href="{% url "new_app" %}?layer={{resource.service_typename}}&amp;storeType={{resource.storeType}}"&gt;{% trans "New App" %}&lt;/a&gt;
              {% endif %}
  </code></pre>
  
  <p>Apparently is not a good practice to "leak" into the core code, code of contrib apps. 
  What would be a good method to delegate this to the application itself?</p>