The `help` module is no longer needed, since `clap` handles that.
This meant that the re-exports of each command's `ABOUT` could be removed and
the `const`s can now be private.
This implementation works around the fact that `clap` does currently
not support value parsers for a series of values, so representing
`--payload` as a `Vec<Payload>` does not work.
Instead, we parse eveything into a `Vec<String>` and do the validation
on the application side.
Using value parsers for a series of values will probably be supported in
`clap` v5, though.
Josh Soref
Lorenz Leutgeb
Adrian Duke
Fintan Halpenny
Erik Kundt