In the pre-community-templates era, we could expose a Flow to external users using the <flow:interview>
component in a Visualforce page.
The Community Builder does not let you add Visualforce pages directly, so I tried to add the Visualforce page, containing the <flow:interview>
component, to a Lightning Component as an iframe (bad idea?).
It kind of works with a very simple Flow, but soon I hit the "Maximum view state size limit (135KB) exceeded" error for the Visualforce page.
Any ideas on how to successfully expose a Flow in a Community using the Napili template (preferably using the Lightning Runtime for Flows)?