Support inverted bool flags, e.g. `--no-all-users`

When creating automated scripts (e.g. for Ansible) user prompts are not desirable.
Currently the "inverse" of `fscrypt setup --all-users` is `fscrypt setup --quiet`
However that is just a workaround, you may actually want the output (e.g. for logging setup steps) but just disable the question by specifying a value

So `--no-all-users` are `--all-users=no` would be great additions.

Start at the CLI entry point for `fscrypt setup` and inspect how its boolean flags are defined and parsed. Add support for the requested `--no-all-users` and `--all-users=no` forms, then verify that they disable the prompt while preserving normal output.

Written by the indexing model from the issue text.