This commit fixes the case when a remote service gets deleted while the
local service remains. Previously the Reconcile on the controller wasn't
called because we weren't returning the deleted Service in the service
informer List method which may leave some EndpointSlice in the cluster
that should be deleted.

In an usual Kubernetes environment this is not an issue since the
OwnerReference should be deleting the EndpointSlices as well.
In our case the actual Service still exist because we have this
mechanism of creating "virtual" service by adding the cluster name in
suffix to trigger a reconcile on each remote cluster.

To fix that we are now returning the combination of all the local
Services and the remote clusters instead of returning all the remote
services. This allows to trigger a reconcile on all the possible
services including some of them that don't exist which would
make the Get method of the Service informer to return a not found error
which will then trigger a deletion via our cleanup hook.

Signed-off-by: Arthur Outhenin-Chalandre <arthur@cri.epita.fr>