Renaming forms 'fields' property to 'elements' as this makes more sense since they can be buttons and other kind of input/widgets besides fields and also to avoid confusion with types 'fields' property that is more related to schema than directly tied to forms and types 'fields' property is an object whilst forms 'fields' property (now 'elements') is an array.
Adding form name to form elements id attribute value prefix to avoid clashing.