Improve the documentation for the node ASK SDK v2
The documentation of the new ASK SDK for node.js (https://ask-sdk-for-nodejs.readthedocs.io/en/latest/) seemed to be missing a few concepts compared to the v1.
It would be good to include more code example inside the documentation (not only the api references), for example, how to setup a PersistenceAdapter, and how to use it.
There's also very little in this documentation about state management and Display Template.
I'm sure there's other stuff that I haven't listed and that were in the previous documentation (https://github.com/alexa/alexa-skills-kit-sdk-for-nodejs/tree/v1.0.25).