Use a file descriptor passed by the launchpad

Use a file descriptor passed by the launchpad

- The application socket path is changed to "/run/aul/apps/<uid>/".
- An aul.service file is added for making /run/aul/apps and
/run/aul/daemons directories. The /run/aul/daemons directory has
the "User::Home" SMACK label to protect sockets of daemon processes
from being deleted by attacker.
- While calling the aul_initialize(), the application can get
the aul listen socketfd by using getenv(). The launchpad sets the
environment variable about the aul listen socketfd before executing an
application.

Change-Id: Ie0e5cbeef12ed96ddeab2cfbd38e355cca2692de
Signed-off-by: Hwankyu Jhun <h.jhun@samsung.com>