Motivation
Not all tools use pre-commit, but it makes sense to keep the interface consistent.

Basically in some cases we might not want to add a tool as a pre-commit, even though it's possible. So we can add this flag to basically treat pre-commit as being unused for the purposes of adding the tool.

If removing the tool, then --no-hook can ignore the pre-commit configuration and not remove from that.

Summary of desired enhancement
Include a --no-hook flag for all tools in the usethis tool subcommand set.