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.

The values can contain bash variables in yaml which will be replaced
for backwwards compatbility.

eg in:
nvidia-gpu:
  enabled: ${NVIDIA_GPU_ENABLED}

${NVIDIA_GPU_ENABLED} will be replaced by the value of the
nvidia_gpu_enabled label.

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