Some users are confused about placement of the debug_level directive or
the location of the log files. Clarify both in the man page.

Also add a pointer to sss_debuglevel.

Reviewed-by: Pavel Březina <pbrezina@redhat.com>

Many lines in debug_levels.xml violated our line-length conventsions.
This patch provides no functional changes, it simply brings those lines
into compliance.

Originally, we planned to deprecate the decimal values for the debug
levels, but that has proven to be too difficult for most users to
understand. Instead, we will document both the simple decimal and
complex bitmask values and recommend the use of the decimal values.

https://fedorahosted.org/sssd/ticket/925

Modified sssd and sssd.conf man pages to reflect new levels.
Added new man include: include/debug_levels.xml