Add suffixHash to ConfigMaps and Secrets passed to SylvaUnitsRelease

Once !251 (merged) will land, SWCO will Inject ConfigMAps and Secrets into workload clusters namespaces to be consumed by SylvaUnitsRelease.

In order to ensure that SylvaUnitsRelease and the corresponding HelmRelease will reconcile as soon as valuesFrom are changed, in a consistent way, we should add a suffix Hash to the names of these ConfigMap and Secrets.

In order to ensure hash computation consistency, we should try to leverage the kustomize library

We should also implement garbage collection and prune old ConfigMaps and Secrets that are not referred any more. For that purpose, we should add a well-known label to retrieve these resources.