Detect system installed compatibility tools

[Revival8697]

Is your feature request related to a problem? Please describe. Yes, ProtonUp-Qt doesn't detect system installed compatibility tools so I can't select them for games.

Describe the solution you'd like Detect the compatibility tools in /usr/share/steam/compatibilitytools.d.

Describe alternatives you've considered I could install them as user but I would prefer them to be updated using the package manager.

Additional context Example:

• https://aur.archlinux.org/packages/proton-cachyos
• https://aur.archlinux.org/packages/proton-ge-custom-bin
• https://aur.archlinux.org/packages/luxtorpeda-bin