adding finalizer option in all manifests and rework its docs (#2521)

docs/reference/operator_parameters.md

@@ -333,11 +333,16 @@ configuration they are grouped under the `kubernetes` key.
   will not add the `spilo-role=master` selector to the PDB.
 
 * **enable_finalizers**
-  By default, a deletion of the Postgresql resource will trigger a cleanup of
-  all child resources. However, if the database cluster is in a broken state
-  (e.g. failed initialization) and the operator cannot fully sync it, there can
-  be leftovers from a DELETE event. By enabling finalizers the Operator will
-  ensure all managed resources are deleted prior to the Postgresql resource.
+  By default, a deletion of the Postgresql resource will trigger an event
+  that leads to a cleanup of all child resources. However, if the database
+  cluster is in a broken state (e.g. failed initialization) and the operator
+  cannot fully sync it, there can be leftovers. By enabling finalizers the
+  operator will ensure all managed resources are deleted prior to the
+  Postgresql resource. There is a trade-off though: The deletion is only
+  performed at the next cluster SYNC cycle when finding a `deletionTimestamp`
+  in the metadata and not immediately after issueing a delete command. The
+  final removal of the custom resource will add a DELETE event to the worker
+  queue but the child resources are already gone at this point.
   The default is `false`.
 
 * **enable_pod_disruption_budget**