Support type triggers (#96)

* implement mirrorlist package generator

* implement keyring package generator

* docs update

* do not skip empty lines

* fill remote source for local packages

* faq update

src/ahriman/application/handlers/validate.py

@@ -78,7 +78,9 @@ class Validate(Handler):
 
         # create trigger loader instance
         loader = TriggerLoader()
-        for trigger in loader.selected_triggers(configuration):
+        triggers = loader.selected_triggers(configuration) + loader.known_triggers(configuration)
+
+        for trigger in triggers:
             try:
                 trigger_class = loader.load_trigger_class(trigger)
             except ExtensionError: