permit customization of sshd config loglevel

This adds a new param which will allow the user to set the sshd configuration setting 'LogLevel' to
'QUIET', 'FATAL', 'ERROR', 'INFO', 'VERBOSE'

There are also debug options supported by sshd, but since each of those levels violate users' assumption of security, I didn't make them supported options. My belief on this is that by allowing those levels to be persisted longer via puppet, we'd be encouraging bad habits.