Make current user online in PHP 

To solve some issues and boost up performance it's needed to move the greet command to PHP.

- [x] Remove greet, session id etc from client 
- [x] generate sessionId in greet command
- [x] execute greet command in `appcontroller::index` 
- [x] add sessionid to initvars
- [x] update client so Chat.och.sessionId = initvar['sessionid']