cargo.sh previously used bash features but only used `sh` in the shebang, and also did not properly quote some variables to avoid splitting/globbing from happening. Also, `-euo pilefail` is now set to avoid other errors that might come up.
This adds a .desktop file (without icon for now), which will automatically be installed when `meson install` is run.
Meson will allow us to: - Verify the used rust compiler is recent enough - Install ressources such as a .desktop files, icons, etc.
