[Linux] Purge on startup using systemd if installed

[WilliamVenner]

There are a bunch of ways to run things at login on Linux. In KDE and Gnome, you can configure these items from the system settings GUI. On anything with systemd, you can set up a service (quite a bit like you've done for macOS with launchd), and of course, you could just use a regular shell script.

https://www.reddit.com/r/software/comments/lrsehh/blackhole_a_semi_temporary_directory_for_windows/goq9g8n/