Refactor of how "event icons" are created, using custom SVG icons for
key outlines and some complex keys. Allows multiple key widths so that
"Ctrl", "Insert", etc can be readable. Strings are automatically sized
rather than hardcoded. Also allows these strings to be translated.
Supports the UI icon alpha preference. Also supports local aspect in
case we ever want to allow 2D zooming there.
Pull Request: https://projects.blender.org/blender/blender/pulls/125591
5fb140a36e