Set<Class<? extends AbstractConfig>> getInjectableClasses() {
        return Collections.unmodifiableSet(configInstanceMap.keySet());
    }
This is sort of the equivalent to stroom's ConfigMapper class.
It holds the de-serialised config objects in a map that is then used to
provide them for guice injection.
stroom-proxy/stroom-proxy-app/src/main/java/stroom/proxy/app/guice/ProxyConfigProvider.java