Fix FHS install dirs (#5930)
Fix FHS install dirs (#5930)

Install .desktop files into /usr/share/applications.
Install PNGs for the above into /usr/share/icons.
Install udev rules into /lib/udev/rules.d.
prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r