Micro service for metadata handling

[mfilter]

a micro service should be created that allows to manage model metadaten from JS code. This should provide functions to read, write, change, combine, convert and delete content of all metadata fields available within dedicated FSM-ML schema verison. This also includes the proper conversion of metadata content in cases where the user changes the model type or where user combine two or more models and the service provide concatenated metadata back (if reasonable). the read, write, change and delete operations are obvious the combine operation should allow to combine two or more metadata fields that share the same "ancestor" in the generic metadata schema (GMS) and provide a "_" -concatenated value back that will be inserted into the GMS of the joined model. It can be assumed that the joining of models will always generate a model of type GMS. The user might change the model type later, but this would then handled by the "convert" services. For metadata of type list combining would simply extend the list, for date/time or numerical fields the first value will provided back. "convert" service: these services handle the conversion of metadata content between different model classes. the only critical business logic decision here is on how to handle cases where the cardinality of a metadata field is reduced during the conversion step. Here the microservice should provide back only the first entry in the "list".
from the same metadata origininput

[schuelet]

• first step: create the micro service that gives a response
• combine approach: convert both models to generic model, then concatenate metadata
• write unit tests for working combinations of conversions

[schuelet]

moving this to testing column. Conversion and Concatenation methods have been implemented in FSK-Lab.