Unify the values of `MouseButton` and thus remove `Other` variant in
limit possible buttons to 32, which was picked based on platform
capabilities, where 32 is the highest.
For the reference, SDL has identical limit.
The API is integrated into the `WindowEvent::Pointer*` API and is
present in form of `TabletTool` variant on corresponding data entries.
For now implemented for Web, Windows, and with limitations for Wayland.
Fixes#99.
Co-authored-by: daxpedda <daxpedda@gmail.com>
