:sparkles: Group descriptions

Several tags explicit the description.

src/templates/main.html

@@ -7,7 +7,6 @@
         <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
 $for(author-meta)$
         <meta name="author" content="$author-meta$" />
-        <meta name="description" content="$description$">
 $endfor$
 $if(date-meta)$
         <meta name="dcterms.date" content="$date-meta$" />
@@ -17,20 +16,24 @@ $if(keywords)$
 $endif$
         <link rel="shortcut icon" href="/favicon.ico"/>
 
+$if(description)$
+        <meta name="description" content="$description$">
+        <meta itemprop="description" content="$description$">
+        <meta property="og:description" content="$description$">
+        <meta name="twitter:description" content="$description$">
+$endif$
+
         <!-- Google / Search Engine Tags -->
         <meta itemprop="name" content="$author-meta$">
-        <meta itemprop="description" content="$description$">
 
         <!-- Facebook Meta Tags -->
         <meta property="og:url" content="https://www.jovian-hersemeule.eu">
         <meta property="og:type" content="website">
         <meta property="og:title" content="$title$">
-        <meta property="og:description" content="$description$">
 
         <!-- Twitter Meta Tags -->
         <meta name="twitter:card" content="summary_large_image">
         <meta name="twitter:title" content="$title$">
-        <meta name="twitter:description" content="$description$">
 
         <!-- Share img -->
 $if(img.share)$