chore: unify finalizers

[tmilos77]

Description

Changes proposed in this pull request:

• add new common finalizer for all CloudManager resources cloud-manager.kyma-project.io/deletion-hook
  • refactor all places old two finalizers were called and use a new one instead
• modify common actions AddFinalizer() and RemoveFinalizer() to use new finalizer
  • keep removing old finalizers as well, since migration can not migrate resources being deleted
  • modify RemoveFinalizer() not to return StopAndForget
  • modify each reconciler flow that calls RemoveFinalizer() and add StopAndForget after it
• add migration func, not an action, since beside CloudManager resources being reconciled there are resources that need finalizer migration as ConfigMap, Secret, PV, PVC, Kyma...
• call the migration func
  • for KCP when CloudManager is started
  • for SKR when CloudManager connects to SKR
• record successful migration outcome so it doesn't have to be executed repeatedly due to performance
  • for KCP with a ConfigMap cloud-manager-finalizer-migration
  • for SKR with a KCP Kyma annotation cloud-manager.kyma-project.io/finalizer-migration: "true"

Related issue(s)

[CLAassistant]

All committers have signed the CLA.

[ijovovic]

lgtm