qmljs: correctly handle required and readonly properties

* correct indentation after required property QTCREATORBUG-24144
* handle required <name> statement
* allow default readoly required reordering
* more permissive than the actual parser (which then will show errors
for invalid sequences)
* backport form QmlDom

Fixes: QTCREATORBUG-24144
Change-Id: I19166ca65d108d533a1ed3748c09e35bcfdbc56d
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

tests/auto/qml/reformatter/qmlreadonly.qml

@@ -2,4 +2,13 @@ import QtQuick 2.0
 
 Item {
     readonly property int horse: 40
+    required property Item theItem
+    required data
+
+    function foo() {
+        theItem.foo("The issue is exacerbated if the object literal is wrapped onto the next line like so:",
+                    {
+                        "foo": theFoo
+                    })
+    }
 }