display notification in dev hub on the header (bug 863472)

media/css/ecosystem/landing.styl

@@ -21,6 +21,14 @@ faded-border() {
     }
 }
 
+.landing .notification-box {
+    cursor: pointer;
+    position: fixed;
+    top: 0;
+    width: 930px;
+    z-index: 300;
+}
+
 #landing-page {
     color: $medium-gray;
     font-size: 14px;

media/js/mkt/ecosystem.js

@@ -87,4 +87,8 @@
 
         self.parent().toggleClass('active');
     });
+
+    $('.notification-box').on('click', function() {
+        $(this).addClass('hidden');
+    });
 })();