add forbiddenKeys method to object

This will allow very interesting modular systems where you can define a global very generic object. Then each module can add their own restrictions using that base object, allowing, disallowing or making required certain properties. Combine this with some default values and you will have a very strong and modular system with high consistency on the results.

Author: danielo515

lib/object.js

@@ -503,6 +503,12 @@ internals.Object = class extends Any {
         children = Hoek.flatten(Array.prototype.slice.call(arguments));
         return this.applyFunctionToChildren(children, 'optional');
     }
+    
+     forbiddenKeys(children) {
+
+        children = Hoek.flatten(Array.prototype.slice.call(arguments));
+        return this.applyFunctionToChildren(children, 'forbidden');
+    }
 
     rename(from, to, options) {