Add a command for uninstalling a tool/all of them

[Dekkonot]

For various reasons, it may be desirable to remove a tool from the file system, or in fact all of them. Rather than relying upon users to locate the install location and delete it, it's probably a good idea to have a command for this.

Off the top of my head, rokit uninstall [tool] and rokit self-uninstall would be good names for the proposed functionality.