Open issues for making wrapper work with non-legacy DataSvc

[tmadlener]

This is a (probably incomplete) list of things that need fixing in order to make the wrapper and the converters work again with the new Frame based I/O in k4FWCore (key4hep/k4FWCore#100). Some of these might require fixes in more than one place at this point. Also they are probably not easily separable, which is also why I put them together into one issue here.

• Collection parameters / cellID encoding string handling. Store the CellIDEncoding strings in the metadata Frame AIDASoft/DD4hep#1140 handles this on the simulation side. There is still the question on how to populate this information in execute during conversions.
• Switch converters over to non-legacy DataSvc. See point above for biggest hurdle
• Fix the clicRec_edm4hep_input test. As also reported in Fix formatting and usage of Legacy components in tests #118 this might be easier to fix once we have a new input file that already has hashed collection IDs