Use a separate function to validate IP address

CURA-6483

cura/Utils/QtUtil.py

@@ -0,0 +1,21 @@
+# Copyright (c) 2019 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from typing import Optional
+
+from PyQt5.QtCore import QObject, pyqtSlot
+
+from . import networking
+
+
+#
+# Exposes the util functions to QML using a QObject.
+#
+class QtUtil(QObject):
+
+    def __init__(self, parent: Optional["QObject"] = None) -> None:
+        super().__init__(parent = parent)
+
+    @pyqtSlot(str, result = bool)
+    def isValidIP(self, address: str) -> bool:
+        return networking.isValidIP(address)