Pluggable Widgets API: Add readOnlyStyle to system properties

System properties is a way for a pluggable widget to adopt extended widget functionality provided by Mendix Platform. The Mendix Platform uses readOnlyStyle to determine if an input field should be rendered as control or as text element. Unfortunately this is unavailable as system property on the widget (and I need it for my custom input widgets =). It would be really nice if we could implement that the same way we use the Editability property

So we don’t need to define on each widget the read only style but we can inherit this from the data view it is placed on.

Please add Read-only style to the supported properties.