Add support for mailing list manager SYMPA

The sympa mailing list manager is capable of virtual domains in so called "robots" and can serve data from various formats: text (via ftp, http, ...), various databases. Packages are available in debian. Basic aliases and transports for postfix can be set in transport-regexp e.g.:

/^.*+owner\@domain\.tld$/                sympabounce:
/^.*\@domain\.tld$/                       sympa:

sympabounce and sympa represent services in master.cf - e.g.

sympa           unix  -       n       n       -       1       pipe flags=RF user
=sympa argv=/usr/lib/sympa/lib/sympa/queue ${recipient}
sympabounce     unix  -       n       n       -       1       pipe flags=RF user
=sympa argv=/usr/lib/sympa/lib/sympa/bouncequeue ${user}@${domain}
Domain owners will be listed in virtual-regexp:
/^(.*)-owner\@(.*)$/                    $1+owner@$2

Eventually aliases retrieved through ispconfig's database are preferable. The web interface can be made available through fpm-wrapper and one aliased virtual host. Example config for nginx:

server {
        listen _default:443;
        listen [2001:db8::1]:443;
        server_name hostname.domain.tld lists.otherdomain.tld;
        root /var/www/lists;
        location / {
                rewrite   ^/$  https://$http_host/home last;
                rewrite   ^/wws/(.*)$   /$1 last;
                rewrite   ^/wws$        /home last;
                fastcgi_param  QUERY_STRING       $query_string;
                fastcgi_param  REQUEST_METHOD     $request_method;
                fastcgi_param  CONTENT_TYPE       $content_type;
                fastcgi_param  CONTENT_LENGTH     $content_length;
                fastcgi_param  PATH_INFO          $fastcgi_script_name;
                fastcgi_param  REQUEST_URI        $request_uri;
                fastcgi_param  REMOTE_ADDR        $remote_addr;
                fastcgi_param  SERVER_NAME        $http_host;
                fastcgi_param  HTTPS            on;
                if (-f $request_filename) { break; }
                if (!-e $request_filename) {
                        gzip off;
                fastcgi_pass   unix:/var/run/sympa/wwsympa.socket;
                }
        }
        location /static-sympa {
                alias /var/lib/sympa/static_content;
        }
}

/var/www/lists/[domain]_css/ will contain css data and may be adapted per domain.

config data will reside in /etc/sympa/hostname.domain.tld

I plea for integration of Sympa as a better alternative to mailman.