Resolve "Support/Helpdesk contact formular"

Closes #38 (closed)

_includes/contact_form.html

+<div id="feedback-form">form will be placed in here</div>
+
+<script type="text/javascript"
+        src="{{ site.directory.vendor | append: 'jquery/dist/jquery.min.js' | strip | relative_url }}">
+</script>
+<script id="zammad_form_script" src="https://hifis-help.hzdr.de/assets/form/form.js"></script>
+
+<script>
+$(function () {
+    $('#feedback-form').ZammadForm({
+        messageTitle: 'Contact HIFIS',
+        messageSubmit: 'Submit',
+        messageThankYou: 'Thank you for your request (#%s). You will hear from us soon!',
+        attachmentSupport: true,
+        noCSS: true,
+    });
+});
+</script>