=== daemon(8) improvements

Links: +
man:daemon[8] URL: link:https://man.freebsd.org/daemon/8[] +
link:https://libera.chat/[Libera IRC] URL: link:https://libera.chat/[]

Contact: Ihor Antonov <mailto:ihor@antonovs.family[]> +
Contact: Kyle Evans <kevans@FreeBSD.org>

An ongoing effort to improve code quality and supervision capabilities of the `daemon` utility.
Daemon is a tool that can daemonize (send to background) or supervise any running process, automatically restarting it if it crashes.
Daemon is widely used in the ports tree and can be used more in base.

This quarter `long_opts` support was added and the codebase went through an initial refactoring phase to prepare it for further changes.
There are no functional changes so far but more changes are coming.
Please contact directly or on `#freebsd-dev` on Libera IRC if you encounter unexpected bugs.

Planned work items for the next quarter:

- use of kqueue for all event sources
- fix link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=268580[Bug #268580]
- fix link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236117[Bug #236117]
- fix link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254511[Bug #254511]
- fix link:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=212829[Bug #212829]
- `procctl PROC_REAP_ACQUIRE`

We are looking for feedback, bug reports (old and new) and feature requests.
