fix(email): do not load local image resources if src tag is an absolu…

…te http url

closes gravitee-io/issues#1972

src/main/java/io/gravitee/notifier/email/EmailNotifier.java

@@ -166,6 +166,7 @@ private void addContentInMessage(final MailMessage mailMessage, final String htm
 
         final List<String> resources = imageElements.stream()
                 .filter(imageElement -> imageElement.hasAttr("src"))
+                .filter(imageElement -> !imageElement.attr("src").startsWith("http"))
                 .map(imageElement -> {
                     final String src = imageElement.attr("src");
                     imageElement.attr("src", "cid:" + src);