Support the Itch game library application

[anderbubble]

LaunchBox should be able to find games installed via Itch, the game distribution application for itch.io.

Itch installs games into a location that isn't detected by the standard LaunchBox "Import Windows game" process.

[Conar McVicker]

Just importing the itch.io library in general would be nice. One of the missing game distro platforms imo