Demo for autosave and restore data

[szygmon]

I've tried it on various systems, and it doesn't always work when automatically saving and restoring data. Could you provide an example/demo of how to use it with sample data to/from DB?

[mikebarkmin]

Here is how I implemented it in my project: https://github.com/openpatch/hyperbook/blob/main/packages/markdown/assets/directive-h5p/client.js