Make SSL and syslog support non-configurable

Make SSL and syslog support non-configurable

Both features have no external dependencies; SSL support requires Qt
to be built with SSL support, and syslog support requires the existence
of the syslog.h header. It makes no sense to make this configurable,
as no additional libraries or other dependencies are pulled in.

Instead, just add them to the feature_summary depending on the prerequisites
being in place.