Update image to v0.4 and prepare for new release

Author: huxcrux

config/manager/kustomization.yaml

@@ -15,4 +15,4 @@ configMapGenerator:
 images:
   - name: controller
     newName: quay.io/elastx/elx-nodegroup-controller
-    newTag: v0.3
+    newTag: v0.4