Add argument / config parameter to convert DER processing to their corresponding asset in PSDM

[johanneshiry]

At the moment, all infeed assets are converted to FixedFeedIn entities with their infeed timeseries attached. It would be nice to have to ability to convert the entities to their PSDM equivalent (e.g. pv -> pv) as configuration parameter.

This would allow using existing models to calculate infeed based on e.g. solar radiation for pv panels instead of using the pre-calculated simbench timeseries.