Should use the instance version

- Subclasses can use this now as expected.
Restructure the default options.

- Flask is now its own section for just flask; added secret field.
- Special section for the JSON flask provider.
Make use of the in-use class rather than default.
Split up the preparation from run.
Should just let integrators adjust that.

- Be secure by default rather than the other way around, now that
  demostrations are done.