Placeholders of Diagram Metadata

[lastradanet]

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Is your feature request related to a problem? Please describe.
Currently, I have to create the same key value pairs for objects in my diagram which share common metadata.

Describe the solution you'd like
I would like to be able to configure diagram metadata or parent object metadata, and use that metadata (via placeholders) in custom object metadata (metadata other than label and tooltip).

Describe alternatives you've considered
Currently, I have to add the same metadata to each object I want to have common metadata.

Additional context

You can see in the final output that the object metadata is not aware of the diagram metadata and thus does not populate. I would like it to be populated with 'nyc'.