use shell script in ~/.local/bin instead of an alias in the *shrc

Not only is it better practice, it's also easier to remove and easier to run in for example steam, which doesn't run the *shrc

The shell script doesn't need to end with .sh btw, so it'll look like a normal binary to the user until they edit it in a text editor, and they'll be able to run ryujinx with just the "Ryujinx" command, without relying on an alias.