Implement setting process label for the given application

Implement setting process label for the given application

This change introduces functions for setting smack label for
application process. They are intended to be used by the app launcher
on application start.

2 variants have been implemented:
1) security_manager_set_process_label_from_binary
   Function extracts smack label from the given application binary and sets
   it for the current process
2) security_manager_set_process_label_from_appid
   Function computes smack label for given application id and sets it for
   current process

Change-Id: I4dfbaf133ec43e292f4ba54023b96a57df439562
Signed-off-by: Jacek Bukarewicz <j.bukarewicz@samsung.com>