Setup DNG SDK 1.5 with internal Libraw to process some rare flavours of DNG...

Setup DNG SDK 1.5 with internal Libraw to process some rare flavours of DNG files (e.g. for 8-bit files).
These files never come from camera or DNG files created by Adobe DNG Converter, but created by some processing
software that uses DNG as intermediate format, aka generated with Nokia 9 PureView.

Screenshot of Nokia 9 PureView items properly decoded in half size (preview) or in full size (editor raw import tool)
with digiKam 7.3.0: https://i.imgur.com/Wi27qUC.png

BUGS: 431689
FIXED-IN: 7.3.0