Convert metadata-converter to twig template

templates/metadata-converter.twig

+{% set pagetitle = 'Metadata parser'|trans %}
+{% extends "base.twig" %}
+
+    {%  set i=1 %}
+{% block content %}
+    <h2>{{ pagetitle }}</h2>
+    <form method="post" enctype="multipart/form-data">
+        <p> {% trans 'XML metadata' %}</p>
+        <p>
+         <textarea name="xmldata" rows="20" style="width:100%">{{ xmldata }}</textarea>
+        </p>
+        <p>
+            {{ 'or select a file:'|trans }}
+
+            <input type="file" name="xmlfile" />
+        </p>
+        <p>
+            <button type="submit" class="btn">{% trans %}Parse{% endtrans %}</button>
+        </p>
+    </form>
+
+    {% if output %}
+
+    <h2>{{ 'Converted metadata'|trans }}</h2>
+
+
+        {% for type, text in output if text %}
+
+    <h3> {{ type }}</h3>
+    <div class="metadatabox">
+        <button data-clipboard-target="#metadata{{ loop.index }}" id="btn{{loop.index }}" class="btn topright" style="margin-right: 0.5em">
+            <img src="/{{ baseurlpath }}resources/icons/clipboard.svg"
+                 alt="Copy to clipboard" />
+        </button>
+        <pre id="metadata{{ loop.index }}">{{ text }}</pre>
+    </div>
+            {% set i=i+1 %}
+        {% endfor %}
+    {% endif %}
+{% endblock content %}
+
+{% block postload %}
+    <script type="text/javascript">
+    {%- for j in 1..i %}
+
+        var clipboard{{ j }} = new Clipboard('#btn{{ j }}');
+
+    {%- endfor %}
+    </script>
+{% endblock postload %}
+