Dsc 392

This request include changes of business rules for Tiff metadata extraction in dsc-392 and dsc-546:
- populate work metadata from tiff metadata extracted for Pictures and Manuscripts only.
   - if the work metatdata field has value set already, don't overwrite with the extracted Tiff data
   - if the work metadata field hasn't value set, set the value to be the corresp. extracted Tiff data
- poplulate copy metadata from tiff metadata extracted for all job types.
   - if the copy metadata field has value set already, overwrite with the extracted Tiff data
   - if the copy metadata field hasn't value set, set the value to be the corresp. extracted Tiff data