fix: set correctly request->session

The session cookie was not created because request->session pointed at
a temporary session.

While here:
- do some cleaning in App
- set request->mount too
- add fcgi_cannot_create_request_delay to the config
- fix: in mailregister plugin get model_connector from env (and not from the request)

winixd/core/config.cpp

@@ -136,6 +136,7 @@ void Config::AssignValues()
 	fcgi_socket_user  		= Text(L"fcgi_socket_user");
 	fcgi_socket_group 		= Text(L"fcgi_socket_group");
 	fcgi_socket_listen		= Int(L"fcgi_socket_listen", 1024);
+	fcgi_cannot_create_request_delay = Size(L"fcgi_cannot_create_request_delay", 3);
 	log_level				= Int(L"log_level", 1);
 	log_request				= Int(L"log_request", 1);
 	log_save_each_line 		= Bool(L"log_save_each_line", false);