Add pod-priority chart
This allows to install the priority classes per cluster. And then this adds to the swh charts services the priority per deployment (which is transitive to the associated pods) [1].
The first commit installs the priorities in the chart cluster-components. Successive commits adds the swh chart adaptation per service to add the proper charts [2]. In dedicated commits so we can ensure with minikube that it's doing the right things. It does.
Currently, this only adds the scaffolding to install priorities (and configure deployments). Nothing is activated for the "production" clusters (production, admin, staging, ...).
This also only concerns the swh services for now. Extra work need to happen to install the priorities on other deployments.
Note: Minikube tests happy.
See [1] for the table with priority and associated pods