docs, net, service-objects: Add a section for Service lifecycle

In v1.9 `virtctl expose` adds a `ownerReference` to the Service object
and binds it to the VM/VMI object.
Allowing proper cleanup of Services and avoiding orphan services.

Signed-off-by: Edward Haas <edwardh@redhat.com>

Author: EdDev

docs/network/service_objects.md

@@ -178,3 +178,15 @@ Use `vinagre` client to connect your VirtualMachineInstance by using the
 public IP and port.
 
 Note that here the external port here (31829) was dynamically allocated.
+
+## Service lifecycle
+
+Service objects may be created explicitly by an user or implicitly
+through the `virtctl expose` command.
+
+While creating the service explicitly, it is up to the user to explicitly
+cleanup the service.
+From v1.9 the implicit service creation through `virtctl expose` adds an
+`ownerRefernce` to the service object, binding the service to the VM/VMI.
+As a result, the service will be collected by the garbage-collector once
+the referenced object (e.g. VMI) is deleted.