Parse args with standard getopt() instead of custom cli module

[slook]

This branch is now for experimentation and demonstration purposes only.

• Changed: Parse args with standard getopt() instead of custom cli module

$ ./bin/soulfind --help
Soulseek server implementation in D
-d --database Database path (default: soulfind.db).
-p     --port Listening port.
      --debug Enable debug logging.
-v  --version Show version.
-h     --help This help information.
$ ./bin/soulfind --protify
Unrecognized option --protify
$ ./bin/soulfind --port
Missing value for argument --port.
$ ./bin/soulfind --port 1234
♥ Soulfind Mar-28-2026 process 2782252 listening on port 1234
^C
A la prochaine...
$ ./bin/soulfind --version
Soulfind Mar-28-2026 (compiled with GNU D 2.100)

This will allow us to do what we want with the new argument options in #81 and #82, we can simply get --log option and process strings in a callback option (see number 8 in the documention for relevant examples) or as an spaced split array with arraySep set to " " (see number 6).

No new options nor functional changes in this PR as to the invoking the program, it works just the same as before.

[mathiascode]

We used getopt in the past, but removed it. See commit 150f4a9 for details.

[slook]

Thanks. I didn't realize that you had made this decision.

This branch is now for experimentation and demonstration purposes only.

It's interesting to know that getopts() removes each argument that is parses because it's good practice to not leave parsed args hanging around in the args for no reason. For instance the --database filename, I don't think our cli.arg_parse() removes them even after it's not needed anymore.