HTTP-TPC transfers to S3 endpoints needs multipart support to be able to accept 5GB+ files

• implemented in Davix (DMC-1134, DMC-1135, source)
• HTTP-TPC push => PUT in the storage implementation
• not available in dCache, ??? (to be checked / discussed)
  • this needs to be tested and fixed
  • seems to work fine with EOS (XRootD)