Event listeners no longer take reporter config in constructor

This also required splitting out Listener factory from
the reporter factory hierarchy. In return, the listener
factories only need to take in `IConfig const*`, which
opens up further refactorings down the road in the colour
selection and implementation.

tests/SelfTest/TestRegistrations.cpp

@@ -48,7 +48,7 @@ class ValidatingTestListener : public Catch::EventListenerBase {
     };
 
 public:
-    ValidatingTestListener(Catch::ReporterConfig const& config) :
+    ValidatingTestListener(Catch::IConfig const* config) :
         EventListenerBase(config) {
         m_preferences.shouldReportAllAssertions = true;
     }