CLI: Use enum_dispatch for subcommand dispatch; remove deprecated run_func

[sjfhsjfh]

Summary

• Replace manual Executable matches with enum_dispatch for Command/Topic.
• Simplify Self_ subcommand struct.
• Add enum_dispatch dependency and update Cargo.lock.
• Fix clippy warnings

Breaking change

• run_func removed. Use run instead.

[phil-opp]

Thanks for the PR!

I'm not a fan of the enum_dispatch macro. While it makes the code shorter, it also makes it more difficult to understand. Before I could just read the code, now I have to look up and read the docs of the macro first. It's not a trivial expansion, so it takes quite a bit of time to understand. And since it's a proc macro, reading and understanding the macro's implementation is quite a bit of work.

This PR also seems to bundle some unrelated changes, such as the breaking removal of run_func. Such changes should go into separate PRs. However, I'm against removing the run_func at this point because it is a breaking change and keeping it around for a bit longer does no harm.