Add a guide for dumping the game using a USB storage device

[Pollot]

Adds a comprehensive guide for dumping the game using a USB storage device instead of a Hard Drive Transfer Cable.

As explained in #952, it is possible to dump the game along with the Title Update using this method. However, the process is not as straightforward as dumping directly from the internal hard drive. For this reason, I have created a separate guide and linked it in the README.

I have kept the format consistent with the other guide and simplified the instructions to be as user-friendly as possible.