Remove most unused Adwaita icons and cursors, it's about 30 mebibytes of raw bullshit that doesn't seem to be missing in any shape or form. Rather sadly, the script is too complex to be rewritten in CMake script.
This saves 21 MiB of MSYS2 libraries, without any adverse effects. The MSYS2 build remains bloated, due to the Adwaita icon theme.
No one bothered to ask whether it /should/ be done. The hamburger needs to be replaced with a file open dialog there.
