[x] If relevant, manual tests have been done to ensure the stability of the whole application and that the involved feature works
[x] Automated tests covering the feature or the fix, have been written, deemed irrelevant (give the reason), or an issue has been created to implement the test (give the link)
[x] The PR or the original issue contains a short summary of the implemented solution.
related to #249
PR Goal
Add preview generation with rawpy:
Implemented solution
Use tiff as intermediate format to reuse Pillow builder (note: may replace pillow py wand when https://github.com/algoo/preview-generator/pull/274 is merged.)
Checkpoints