Request: example yamls for ROI'ed dexelas be added to detector yamls

[adas42]

It would really help me work with users if latest iterations of detector yamls were populated under say: hexrd/resources/detector_templates

[psavery]

@adas42 so I do have a version of the composite dexelas in the state file here. I've also attached the instrument yaml as a .txt file (because GitHub won't let me upload a yaml) here.

I'm not sure if it's the latest iteration, or even where it came from. We might have to ask some users to determine which iterations are the latest.