Move Daemon to stoqlib

Avoid importing stoq inside stoqlib. Also, since the daemon runs in another
thread now, we don't need all the "main" logic, just the Daemon object.

Also, remove the need to create a file to identify the service port as we can
make a communication between threads directly.

Change-Id: I2b24ea777627c2459bf93c11887a665074560c3c