U4-5386 Filter out items with type for the Media Picker data type

It would be helpful if a developer could specify a list of media types to filter out when an editor is selecting from the media picker. For example, if a developer wants to make sure an image is only selected and not a folder. This pull requests adds a pre value field to the Media Picker and Multi Media Picker so that a developer can add a comma separated list of Media Types to filter by when displaying the Media Picker.