RAD-109 Generate StudyInstanceUid according to DICOM
generate DICOM UID and set the RadiologyStudy.studyInstanceUid with it when a
new study is saved to the database and the field is not yet set.
* add DecimalUuid to translate UUID into decimal representation
* make RadiologyStudy a BaseOpenmrsData so we know creator, updatedBy
* add private method RadiologyStudyServiceImpl.setStudyInstanceUidIfBlank
* add DicomUidValidator
* clear config and RadiologyProperties from DICOM UID settings we do not use
