tis: add basic tests, don't register unless certs

* fixes a crasher bug (missing config_options in load_config)
* added test coverage for register() and set up
* don’t register hooks unless certs are present
Merge branch 'config-plugins' into toaster
Merge branch 'dkim' into toaster
Merge branch 'geoip' into toaster
Merge branch 'http-server' into toaster
Merge branch 'tls' into toaster
Merge branch 'watch-http' into toaster