* If the source is an array, it is returned unchanged.
* If the source is a string, is is converted depending on CONFIGURATION_STRING_FORMAT,
which can be STRING_FORMAT_CSV or STRING_FORMAT_JSON. For CSV the delimiter can be
set via CONFIGURATION_STRING_DELIMITER.
* If the source is a PersistentResource object, it is converted to an array. The actual resource
content is either embedded as base64-encoded data or saved to a file, depending on
CONFIGURATION_RESOURCE_EXPORT_TYPE. For RESOURCE_EXPORT_TYPE_FILE the setting
CONFIGURATION_RESOURCE_SAVE_PATH must be set as well.