Do not embed the templates and static files in the binary

templates/components/back_to_client.html

@@ -0,0 +1,30 @@
+{#
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+#}
+
+{% macro link(text, class="", uri, mode, params) %}
+  {% if mode == "form_post" %}
+    <form method="post" action="{{ uri }}">
+      {% for key, value in params %}
+        <input type="hidden" name="{{ key }}" value="{{ value }}" />
+      {% endfor %}
+      <button class="{{ class }}" type="submit">{{ text }}</button>
+    </form>
+  {% elif mode == "fragment" or mode == "query" %}
+    <a class="{{ class }}" href="{{ add_params_to_uri(uri=uri, mode=mode, params=params) }}">{{ text }}</a>
+  {% else %}
+    {{ throw(message="Invalid mode") }}
+  {% endif %}
+{% endmacro %}