sites domain_id and system user overload in remoting p.o.c.
This is a "proof of concept" for forcing a specific system_user for a web site domain created via the remoting api. The code will update the domain_id of the site right before calling the plugin for the site vhosts.
The site vhost plugin decides the system user and system path based on the domain id. For example domain_id 200 will get system user web200 and (usually) path /var/www/clientX/<system_user>/
To specify the domain_id, it has to be passed in the $params array. If not present, the function will use whatever domain_id results fro the sql INSERT operation.
TODO: -) Check if the domain_id is already present before overloading it.