Use simpler and less restrictive server url regex

The old regex was too restrictive. The new one will allow invalid urls, but we don't gain anything from preventing that

BUG: 486888

src/qml/ServerComboBox.qml

@@ -130,7 +130,7 @@ QQC2.ComboBox {
                 }
 
                 validator: RegularExpressionValidator {
-                    regularExpression: /^[a-zA-Z0-9-]{1,61}\.([a-zA-Z]{2,}|[a-zA-Z0-9-]{2,}\.[a-zA-Z]{2,3})$/
+                    regularExpression: /^([^.]+\.)+[^.]+$/
                 }
 
                 Connections {