Add flag to control the behavior of `onChange`

[Lukas742]

With React, the native change (onChange) is fired on every keystroke unlike it does with the custom change event of the UI5 Web Components, which is only fired on blur, ENTER or some other interactions like selecting an option of a Select.

We should add a flag that enables the default behavior of React for the onChange, so app developers can decide on their own how they want to handle this.