Fixes: #19953 - ConfigTemplate debug rendering mode (#21652)

Add debug field to ConfigTemplate and (if True) render template errors
with a full traceback.

netbox/templates/extras/configtemplate.html

@@ -33,6 +33,10 @@
             <th scope="row">{% trans "Attachment" %}</th>
             <td>{% checkmark object.as_attachment %}</td>
           </tr>
+          <tr>
+            <th scope="row">{% trans "Debug" %}</th>
+            <td>{% checkmark object.debug %}</td>
+          </tr>
           <tr>
             <th scope="row">{% trans "Data Source" %}</th>
             <td>

netbox/templates/extras/object_render_config.html

@@ -66,7 +66,13 @@
         {% elif error_message %}
           <div class="alert alert-warning">
             <h4 class="alert-title mb-1">{% trans "Error rendering template" %}</h4>
-            {% trans error_message %}
+            {% if config_template.debug %}
+              <div class="overflow-auto" style="max-height: 30rem;">
+                <pre class="mb-0">{{ error_message }}</pre>
+              </div>
+            {% else %}
+              <pre class="mb-0 text-warning-emphasis bg-transparent border-0 p-0">{{ error_message }}</pre>
+            {% endif %}
           </div>
         {% else %}
           <div class="alert alert-warning">