~ruther/nix-fpga

ref: f618f1a0e7c1ac5e3ff8b6b99ecc006cdcaef8bc nix-fpga/pkgs/xilinx/ise d---------
fix: ise udev
feat: add usb-driver to ISE
fix: ise udev
fix: update ISE udev rules
fix: require INSTALL_DIR only in final packages, not in shells
feat: add executables to fhs package, split to individual frameworks