Improve Dehaze for Raw files - Raw black point

[Desmis]

#5769 Thanks to Ingo Weirich @heckflosse for this algorithm for Bayer and X-trans sensors which allows in the majority of cases to significantly improve the Dehaze process.

I only added "Dehaze" checkbox in Raw black point (Bayer and X-trans), and of course the whole process to update the sliders. (improccoordinator, rtengine, etc.)

Jacques