Replace Bitnami usage in dCache regression tests

It seems that Bitnami has started pulling its images offline. This was the reason for the pipeline failure yesterday: #1292 (closed)

At the moment, only the dCache regression tests are still making use of the Bitnami charts/images: https://gitlab.cern.ch/cta/CTA/-/blob/main/continuousintegration/orchestration/deploy_dcache.sh?ref_type=heads

As a result, the regression tests are failing. See e.g. https://gitlab.cern.ch/cta/CTA/-/jobs/61701277

If we want the dCache regression tests to work again, we should aim to replace those charts/images by something else.