Release bare shell{aa64,arm,ia32,riscv64,x64}.efi files

[kc2zgu]

The ISO image is useful for making bootable media on a dedicated device, but I expect many people will also want to add a shell executable to an existing system with its own EFI partition. The extra step of extracting the files from the iso image isn't too difficult, but since they need to be renamed to "shell" instead of "boot" this makes it a little more cumbersome when you don't want to clobber an existing default bootloader.

It would be nice to have the shell files available individually in the releases with the "shell" filenames.

[pbatard]

I'll see what I can do for the next release.

[FoxieFlakey]

this would be nice too for some people who just want the .efi file precisely and dont want to deal with mounting/extracting from ISO