Merge branch 'stable-3.1' into 'stable-3.1'

Backport of !925

See merge request ispconfig/ispconfig3!1014

Author: Marius Burkard

interface/web/themes/default/assets/stylesheets/ispconfig.css

@@ -794,4 +794,8 @@ span.notification_text {
 	color: red;
 	background: #fdd;
 	text-decoration: none;
-}
+}
+#apache_directives, #nginx_directives, #proxy_directives {
+	font-family: Consolas, "Courier New", Courier, monospace;
+}
+