[IMP] website_forum: Display a summary card on shared forum posts on twitter

See: https://dev.twitter.com/cards/types/summary

addons/website_forum/views/website_forum.xml

@@ -720,6 +720,13 @@
 
 <!-- Specific Post Layout -->
 <template id="post_description_full" name="Question Navigation">
+    <t t-set="head">
+        <meta name="twitter:card" content="summary" />
+        <meta name="twitter:site" t-attf-content="@#{res_company.name}" />
+        <meta name="twitter:title" t-att-content="question.name" />
+        <meta name="twitter:description" t-att-content="question.content" />
+        <meta name="twitter:image" t-attf-content="#{request.httprequest.url_root}forum/user/#{question.create_uid.id}/avatar"/>   
+    </t> 
     <t t-call="website_forum.header">
         <div class="alert alert-info text-center" role="alert" t-if="forum and question.state == 'pending' and user.karma>=forum.karma_moderate and question.active">
             <a t-attf-href="/forum/#{slug(forum)}/post/#{slug(question)}/validate" type="button" class="btn btn-success">Accept <i class="fa fa-check"/></a>