Detect Lens info from in camera list description for manual lenses on Nikon Zf

Is your feature request related to a problem? Please describe.

I have a similar problem with the images from my Nikon Zf as described in #18636 and this will also be the case for other Z cameras such as the Z6III, Z8, Z9. From firmware 2.0 the camera offers the possibility to create a list for lenses without CPU in which the lens name, the focal length and the speed of each lens can be entered. If a corresponding lens is used on the camera, it can then be selected from the list. The aperture set on the lens can be adopted on the camera using a selection dial. Unfortunately, this data is only stored in the Exif.Photo data. However, Darktable only reads the Exif.Nikon data and recognizes Manual Lens No CPU

exiv2 -pt DSC_0034.NEF | grep -i Lens
Exif.Nikon3.LensType                         Byte        1  MF 
Exif.Nikon3.Lens                             Rational    4  n/a
Exif.Nikon3.LensFStops                       Undefined   4  0
Exif.NikonLd4.LensIDNumber                   Byte        1  Manual Lens No CPU
Exif.NikonLd4.LensFStops                     Byte        1  F0.0
Exif.NikonLd4.LensID                         Short       1  0
Exif.Photo.LensSpecification                 Rational    4  n/a
Exif.Photo.LensMake                          Ascii       6  
Exif.Photo.LensModel                         Ascii      65  Summicron-M 1:2/50
Exif.Photo.LensSerialNumber                  Ascii      11  

Describe the solution you'd like

If Darktable recognizes "No CPU", the Exif.Photo data should also be evaluated.

Additional context

Nikon_Zf_exif_data.zip