Polymorphy in Archive queries

The archive query seems to have problems with requests that target properties in subclasses.

For example, we have the subsection: EntryArchive.workflow: Workflow and a subclass SimulationWorkflow(Workflow). Now only SimulationWorkflow has a subsection results and Workflow has not. Here an archive like this

workflow:
  m_def: SimulationWorkflow
  results: ...

cannot be queried with

{
  "workflow": {
    "results": *
  }
}

Polymorphy is a rather new concept in the metainfo, but is important for all ELN data and the new workflow section. It might also affect the nexus data.