Make clear Default is Demo Training Dataset on Exhaustive Page

[richard-churchman]

For reasons of being able to demonstrate the Exhaustive training functionality in the default installation Exhaustive training a model on a demonstration dataset. The absence of a clear message may lead users to wonder what the platform is not training on data tagged or laid out in the database.

Create a clear splash note on the page that makes it clear that it is targeting demonstration data, make the dataset available for download or inspection, and mention the environment variable that needs to be changed for production data to be used.