Deprecate: PodioInput, k4DataSvc, PodioDataSvc, (FCCDataSvc)

[andresailer]

Only the IOSvc must be used for new code from now on

• Add deprecation warnings
• Document migration towards IOSvc
  • https://key4hep.github.io/key4hep-doc/how-tos/k4fwcore/doc/PodioInputOutput.html#migrating-from-the-legacy-k4datasvc
• Eventually remove PodioInput / k4DataSvc

[m-fila]

The services to be deprecated are still advertised in the documentation:

• key4hep-doc - Use IOSvc in writing algs docs key4hep-doc#92
• key4hep-tutorials - Update tutorials to use IOSvc and functional algorithms key4hep-tutorials#21
• k4MarlinWrapper- Use IOSvc by the default in docs and examples k4MarlinWrapper#227

[tmadlener]

We need to make sure that Gaudi::Algorithms are still supported, I think. They still use DataHandle and there might be some subtleties in the fact that a DataHandle doesn't store things as an AnyDataWrapper into the TES. This is currently causing an issue in key4hep/k4MarlinWrapper#219

[tmadlener]

These are also injected by default in k4MarlinWrapper: key4hep/k4MarlinWrapper#231