Introduces a new option --debug-to-files which makes SSSD output its
debug information to a file instead of stderr, which is still the
default.

Also introduces a new confdb option debug_to_files which does the same,
but can be specified per-service in the config file.

The logfiles are stored in /var/log/sssd by default.

Changes the initscript to log to files by default.

This converts a great many configuration options to the new
standard format.

This reverts commit 8c50bd085c0efe5fde354deee2c8118887aae29d.

Amended: commit 1016af2b1b97ad4290ccce8fa462cc7e3c191b2e also made
use of the SYSLOG_ERROR() macro, so those portions of that code
also needed to be reverted.

This is just a band-aid until ELAPI is fully functional and ready to
use.

Because the confdb always operates synchronously, it maintains its
own private event context internally. The event context argument
passed to it is never used, so we'll remove it to avoid confusion.

The child processes call prctl() and when their parent process is
killed, they are sent SIGTERM using prctl. This is currently
Linux-specific, for non-Linuxes, a similar effect is achieved by
catching a set of common termination signals and sending SIGTERM to the
process group.

use '--debug-timestamps' at the command line
or set 'debug-timestamps = TRUE' in the configuration file.

Use tevent signal handling facilities for handlong SIGTERM and SIGINT in the monitor.

Remove pidfile on SIGTERM and SIGINT.

Make sssd single-instance by checking if we suceeded in signaling the process in the pidfile.