poold: Move poold.cc to its own directory

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Copy namespace class definitions to poold.hh

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Remove class definitions

Include new poold.hh header file and remove class
definitions.

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Move Logger class to logger.cc

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Move System class to system.cc

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Move Socket class to socket.cc

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Move Epoll class to epoll.cc

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
poold: Move SigHandler class to sighandler.cc

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
cmake: Include new files to build process

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>