Provide a way to set the key binding prefix

[ambihelical]

In https://www.gnu.org/software/emacs/manual/html_node/elisp/Key-Binding-Conventions.html, it says that "Sequences consisting of C-c followed by a control character or a digit are reserved for major modes. "

I don't know how important these conventions are to follow, but personally, I'd like it if I could set the prefix that this minor mode uses. That would satisfy the conventions and also make it more flexible.