Currently logging configuration is splitted in two distinct classes, the init.pp and the
logging.pp classes.
This review aims to centralize all logging related parameters in a
single class, the logging.pp one.
The impacted parameters are :
* use_syslog
* use_stderr
* log_facility
* verbose
* debug
* log_dir
This change remains backward compatible with what is currently in place
Change-Id: I1132395295f542f4ba5459769a5b4b829a9cd7a7