sss_tools: add test if sssd is running Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

TOOLS: New helper tool sss_signal A minimal tool whose only purpose is to signal the monitor with SIGUSR2. The tool will be executed by the system bus in order to provide system activation, so it's packaged in libexec. Reviewed-by: Pavel Březina <pbrezina@redhat.com>