Description

Add new diagnostics name metadata field to be used by the constituents object*

*Note: for now, the new metadata field will only be used by the constituents object, but can be extended to be used by the amorphous future diagnostics object (#579)

Related to #461

Solution

1. Add new optional metadata field - diagnostic_name - to the metadata.
2. Add new diagnostics name attribute to the constituents object that is set to the diagnostic name field in the metadata (or through the instantiate call)