LibWeb+WebContent: Setup the js console client earlier

This allows us to print messages in inline scripts. Also add an example
of this in the welcome page to test this.

Base/res/html/misc/welcome.js

@@ -1,3 +1,6 @@
 document.addEventListener("DOMContentLoaded", function () {
+    console.log(
+        "Hello from DOMContentLoaded! There should be a message before this from an inline script"
+    );
     document.getElementById("ua").innerHTML = navigator.userAgent;
 });