Annotations to guide RDM tools about which quantities to index for deep and exhaustive appdef instance data

[mkuehbach]

https://gitlab.mpcdf.mpg.de/nomad-lab/nomad-FAIR/-/issues/2012
Assume richly contextualize instance data of NeXus appdef files are loaded in RDM systems, which concepts should be indexed with which priority
Development of a mechanism whereby RDM system can be instructed which quantities to pick up and index for e.g. search capabilities,
all required concepts, none, conflict of interest between appdefs for different target applications,