[cern] Add cern_chart_values label

cern_chart_values is a bsae64 --wrap=0 encoded string that stores the helm values of the cern metachart. https://gitlab.cern.ch/helm/releases/cern-magnum/-/blob/f60ddc94c7264d3968b07f62048a17d8cbbfdeea/values.yaml

If the values exist labels like monitoring_enabled, logging_producer will have no effect since they should be defined in the values file.

The values will be decoded, indented and writen in the ConfigMap of the install-cern-chart job.

If cern_chart_values is "" (the default value), the cern_chart will be installed with the values already in helm/cern-chart.sh.

Change-Id: I93319d2a42fc52fe3d9966e04008eac34eb7e927 Signed-off-by: Spyros Trigazis spyridon.trigazis@cern.ch

OS-13581