Actually use the buffer not it's location on the stack.

The local provider needs no backend, so we'll create a special
provider entry for it called "local" that will not attempt to
retrieve provider configuration but will remain in the service
list so it can be updated when the config file changes.

Refactoring the confdb so that the setup code can be linked
separately from the access API. This is being done so that our
plugins do not need to link against the collection and ini_config
libraries.

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.

In the event that the configuration was corrupt the first time the
SSSD is started, it would write in the special data for attributes
and indexes, but it would fail before writing the version.

Subsequent reloads (even with correct configuration files) would
fail, since they would try again to write the attributes and
indexes and fail since they were already present.

Also convert all places where we were using custom code to parse
config arguments.
And fix a copy&paste error in nss_get_config