Adds default configuration for bootstrap.use_pydap

I noticed that pyon.yml didn't even have an example for how to configure and launch the registration process, which resulted in a piece of tribal knowledge. This at least provides a default value and an example for how to configure.

Part of [OOIION-1404](https://jira.oceanobservatories.org/tasks/browse/OOIION-1404)