Add option to let the scroll rather than zoom with the mouse wheel

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

In the darkroom, I primarily zoom with keyboard shortcuts, (and if https://github.com/darktable-org/darktable/issues/18048, was implemented, I'd use for pinch-to-zoom).

To me, the fact that the scrollwheel over the image (or scrolling on the touchpad) also zooms is unwelcome, and I would much prefer if it controlled actual scrolling.

Describe the solution you'd like
Add an option to switch from "mouse wheel over image in darkroom zooms" to "mouse wheel over image in darkroom scrolls". Maybe that could be placed in the Miscellaneous tab, next to "mouse wheel scrolls modules in side panels by default".

Preferably, that should also take effect in the optional second darkroom window () as well, when shown.

Alternatives
Zooming with the mouse and scrolling with the keyboard is already available, but I'm not a fan.
Scrolling by pressing a key and dragging is also already available, but I like it less as well.

Start by tracing how the darkroom handles mouse-wheel input over the image and where the Miscellaneous preferences are defined. Check how the optional second darkroom window receives the same input. Done means a user-selectable zoom-versus-scroll behavior works in the main darkroom and, when shown, the second window.