add initial support for offline engines && command engine

searx/templates/simple/result_templates/key-value.html

@@ -0,0 +1,11 @@
+<table>
+    {% for key, value in result.items() %}
+    {% if key in ['engine', 'engines', 'template', 'score', 'category', 'positions'] %}
+        {% continue %}
+    {% endif %}
+    <tr>
+        <td><b>{{ key|upper }}</b>: {{ value }}</td>
+    </tr>
+    {% endfor %}
+</table>
+<div class="engines">{% for engine in result.engines %}<span>{{ engine }}</span>{% endfor %}</div>{{- '' -}}