opengraph embed support

iwm_browser/templates/levelInfo.html

@@ -10,6 +10,12 @@
                    '/static/search/search.css',
                    '/static/search/searchResults.css'
                    ) }}">
+        <meta content="{{ map['Name'] }}" property="og:title" />
+        {% if map['Description'] != '' %}<meta content="{{ map['Description'] }}" property="og:description" />{% endif %}
+        <meta content="https://iwm-browser.magmaus3.eu.org/level/{{ map['ID'] }}" property="og:url" />
+        <meta content="{{ THUMB_URL }}" property="og:image" />
+        <meta content="IWM Browser" property="og:site_name" />
+        <!-- <meta content="#43B581" data-react-helmet="true" name="theme-color" /> -->
         <!-- Optional features -->
         <script>
             function copy(obj) {