device-lenovo-21bx: various improvements

- usbguard config: these are builtin USB devices that should be allowed
  by default

- removed nonfree-fw package, I decided that everything from that should
  be required since some fairly major features are broken without these
  firmwares and relevant userspace apps

- re-enabled EFI runtime services
        - Laptops need the "Linux Boot" option enabled
        - "With recent UEFI firmware efi=noruntime can be left out when
          the Linux Boot option is enabled."
        - https://github.com/jhovold/linux/wiki/X13s#kernel-command-line