refactor: manage state associated with a resource in a single spot

Fixes #1314

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/EventProcessor.java

@@ -40,7 +40,6 @@ class EventProcessor<R extends HasMetadata> implements EventHandler, LifecycleAw
   private final Metrics metrics;
   private final Cache<R> cache;
   private final EventSourceManager<R> eventSourceManager;
-  // private final EventMarker eventMarker = new EventMarker();
   private final RateLimiter<? extends RateLimitState> rateLimiter;
 
   private final ResourceStateManager resourceStateManager = new ResourceStateManager();