Enable setting default endpoint to start from dashboard

Observing others that were setting up eShop and using the web front-end as the startup project, I let them know eShop is now an Aspire app and should use AppHost as the startup. An observation was that they still wanted an 'app' to run on F5 and not just the Dashboard.

Consider some means of specifying a resource's endpoint to be further 'launched' after all are ready state. This would save some clicks in an inner loop.