add remove/delete subcmd

Currently, there is only a "disable" subcommand, but I think a "remove" (or "delete") subcommand should be added.

The function of "disable" is generally to temporarily disable for a short or long time, and there is a high possibility of using it again in the future; sometimes it is certain that a source will not be used again, then the "remove" subcommand is needed.

Only disabling will cause more and more things in the sources.list.d directory, which is not easy to manage.