Add modifier to adjust sliding sensitivity

[williamchange]

via discord

would it be possible to implement something similar to what blender has: while dragging a parameter slider, rotating your mousewheel would increase/decrease it's sensitivity? After some tests with 1.7 slider sensitivity settings I feel like it does not work well as with transform nodes user usually wanna have more finer control, but setting it low makes slides like blend very tedious to work with.

This adds a mousewheel modifier(while param is in sliding mode) to adjust sliding sensitivity for float parameters.

It replaces the preference item, though this is still global and not per-input and is persisted across sessions.

demo-v2.mp4