track and garbage collect orphaned resources

[a-hilaly]

Feature Description

Currently kro does not track resources that become orphaned when users modify a ResourceGroup's templates or change includeWhen conditions. we need to add a managedResources (maybe there is a better name) status field to instances to track owned resources, and implement garbage collection after successful reconciliation. This will ensure that resources are properly cleaned up when they are removed from templates or when includeWhen conditions change from true to
false.

Example:

apiVersion: kro.run/v1alpha1
kind: Application
metadata:
  name: my-application
spec:
  name: my-app
  ingress:
    enabled: false  # When this changes from true to false, the ingress should be GC'd
status:
  managedResources:  # New status field tracking resources
    - kind: Deployment
      name: my-app
      namespace: default
    - kind: Service
      name: my-app-service
      namespace: default
    - kind: Ingress
      name: my-ingress
      namespace: default