Use _user modified_ WB multipliers with modern chromatic adaptation

[kofa73]

Is your feature request related to a problem? Please describe.
I would like to use a grey card to pick WB multipliers in white balance, but still use the 'modern' workflow. Picking WB coefficients would guarantee perfect WB right from the start, but color calibration could still to its magic.
This would clean up confusion when WB is to be copied from a reference shot (with a grey card) to others: the pair of white balance and color calibration would be copied over to all images in the set.

Describe the solution you'd like
Treat whatever multipliers are used in white balance the same way as in-camera multipliers are used in 'as shot to reference_ mode.

Alternatives

• Fall back to 'legacy' for such situations: turn off color calibration and copy over the WB multipliers to all images in the set;
• Copy over white balance, use D50 (same as pipeline) in color calibration.

Additional context
https://discuss.pixls.us/t/copy-paste-manual-white-balance/47333/

[lintujuh]

I'd like to extend this FR.

I have customized D65 settings in WB module, as instructed in one of the old AP's posts. I'd like 'as shot to reference' utilize those coefficients instead of the system camera reference. I'd like this to be possible either with the 'as shot' WB, or like in @kofa73 's FR with customized WB coefficients.