Support multiple filenameTags in DirectoryStorageService #21
Description
I would welcome if filenameTag could be extended to support multiple tags similar to how structure works. For example, I would like to combine the (last entry of, see #22) ImageType and InstanceNumber tags to get filenames such DERIVED_PET_NORM_1.dcm etc., for example, by stating filenameTags="ImageType_InstanceNumber".