Support for Sony ARQ files

[cytrinox]

No description provided.

[cytrinox]

Good resource for ARW/ARQ: https://github.com/lclevy/sony_raw

[lclevy]

Do you see any possible improvement?

[cytrinox]

I laughed at the lossless compression comment 😄
I wasn't aware of the different versions, I just ported the decoder from rawloader and libraw over and added the metadata parser. Maybe I should cleanup my code a little bit.
I'm missing some information about the LJPEG compression (component count, predictor) as there is currently some confusion (e.g. darktable-org/darktable#8523)
I've not discovered any problems so far but to keep track of this task I've created #183. Maybe my code just works and I can close this 😄

Another thing that should gets documented is the various decryption routines required to decode ARW. I've ported them from exiftool into dnglab to decode metadata. But for now I'm unable to tell which format version needs "special care".

Beside these two missing points, great work and it was very helpful to understand the history of this file format. 👍