Put all the logging related parameters to the logging class

Put all the logging related parameters to the logging class

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