Process heating export with custom materials

[koay9f]

Describe the feature
When exporting a PH with custom materials/database options used, the custom material database comes along

Describe MEASUR location
Process Heating Assessment, Custom Materials.
Treasure Hunt (if process heating assessment is tied & for lighting calc once that is complete).
Import/Export pages

Describe MEASUR UI
Should we ask users (who would say no?)?.
Would be nice if we didn't have to import separately. How can we do this well?

Who should verify
Kristina

Optional

Feature requested by
Kristina & Sachin

Sample Inputs and Results
Include input testing values and expected results

Future Integrations
We already have plans for improving the TH imports. Also, we already have MEASUR say "this is the wrong import file". If at least on the dashboard page the import could go "Oh this is a TH opportunities" or "Oh this is a custom material" and help the users make the import happen (for a TH, ask "what TH do you want to import this to"?), that would be good