Add option to return only the optional interface list, some code needs only that.
Add option to return only the optional interface list, some code needs only that.

NewEraCracker/pfsense,NewEraCracker/pfsense,NewEraCracker/pfsense,jxmx/pfsense,brunostein/pfsense,brunostein/pfsense,ch1c4um/pfsense,pfsense/pfsense,ptorsten/pfsense,ch1c4um/pfsense,ch1c4um/pfsense,jxmx/pfsense,phil-davis/pfsense,ptorsten/pfsense,dennypage/pfsense,BlackstarGroup/pfsense,phil-davis/pfsense,NOYB/pfsense,brunostein/pfsense,phil-davis/pfsense,BlackstarGroup/pfsense,jxmx/pfsense,dennypage/pfsense,phil-davis/pfsense,NOYB/pfsense,BlackstarGroup/pfsense,dennypage/pfsense,pfsense/pfsense,NOYB/pfsense,pfsense/pfsense,ptorsten/pfsense,BlackstarGroup/pfsense,NewEraCracker/pfsense,dennypage/pfsense,ch1c4um/pfsense,pfsense/pfsense