Complete the integration of Swiss storage into Rucio data lake

The priority for integrating the Swiss SRC into the Data Lake will be given to the solution which results in a fully functioning Rucio Storage Endpoint. Currently, this is expected to be an xrootd server endpoint. It will be explored which kind of storage backend is more appropriate (e.g. CephFS or RBD).

Less priority will be given to finishing the existing S3-based endpoint, since some limitations are expected with this solution. If time allows it, the S3-based RSE will be setup and tests will be run to determine and document what works and what doesn't.