Streamline export API #753
Description
This issue is to collect ideas and discuss approaches to streamlining and/or improving the API that exports variables from the flowsheets to the WaterTAP UI, which is currently the add() method of the FlowsheetExport class in the fsapi module.
Note that ideas about coordinating with Pyomo annotations are valid, but currently there are no plans to do away with this "shadow" representation entirely (it is useful and simpler to use for the UI, and does have the possibility, unlike annotations, of representing multiple "views" of the same model). How to move this implementation into IDAES core, if this is what happens, is out of scope for this discussion.