Add --user/--group options to lmConfigEditor and lemonldap-ng-cli (user:group hardcoded to apache may not work correctly)

Summary

Attempting to use lmConfigEditor gives errors about being unable to read configuration files. In order to make lemonldap-ng work with nginx, everything has to be owned nginx:nginx instead of apache:apache, but hard coding the user and group in this utility makes it impossible to use with anything other than apache.

Design proposition

add CLI options to specify --user and --group to override apache:apache.

I'm not a PERL master, but I made it work with this

use Getopt::Long;

our $opt_user = 'apache';
our $opt_group = 'apache';
GetOptions (
        "user=s" => \$opt_user,
        "group=s"   => \$opt_group
)
or die("Error in command line arguments\n");

eval {
    setgid( ( getgrnam($opt_group) )[2] );
    setuid( ( getpwnam($opt_user) )[2] );
    print STDERR "Running as uid $EUID and gid $EGID\n";
};