feat: add start method as entrypoint and output version information

Fixes #313
Fixes #314

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/Operator.java

@@ -28,6 +28,15 @@ public Operator(KubernetesClient k8sClient, ConfigurationService configurationSe
     this.configurationService = configurationService;
   }
 
+  public void start() {
+    final var version = configurationService.getVersion();
+    log.info(
+        "Operator {} (commit: {}) built on {} starting…",
+        version.getProject(),
+        version.getCommit(),
+        version.getBuiltTime());
+  }
+
   public <R extends CustomResource> void register(ResourceController<R> controller)
       throws OperatorException {
     register(controller, null);