Reverse Scrollable Input Direction setting

### Enhancement Summary

This feature would add an option in the Settings menu to change the scroll direction of scrollable inputs, such as knobs, sliders, and spinboxes. The default scrolling direction on Windows and Mac (I believe) makes an upwards motion on the scroll wheel or touchpad scroll downwards and decrease values, so for anyone with those settings elsewhere, it would allow LMMS's native UI elements to respond intuitively without changing the OS's global setting. One potential drawback might be that input elements in VSTs wouldn't respond to this setting and might scroll a different direction.

### Implementation Details / Mockup

Ideally, this would add an optional toggle to one of the pages in the Settings menu to enable or disable it, and when enabled, it would reverse the scrolling behavior of all scrollable elements in LMMS.

### Please search the issue tracker for existing feature requests before submitting your own.

- [x] I have searched all existing issues and confirmed that this is not a duplicate.

The issue names no files, tests, or entry points. Start by locating the Settings menu and the implementations of scrollable knobs, sliders, and spinboxes, then determine how one preference could affect them consistently. Done means the setting reverses native LMMS input scrolling while leaving its disabled behavior unchanged.

Written by the indexing model from the issue text.