Create sample data to develop with

[Stormheg]

Context
We would like new contributors to help us with some of the issues. They need some content to work with. It's not feasible to give everyone a backup of the database, as this contains private information that we cannot share outside of our trusted contributors. We could create a cleaned database dump but this would go out of date quickly and thus isn't too helpful either.

Envisioned solution
Create a setup script similar to python manage.py load_initial_data that exists for bakerydemo: https://github.com/wagtail/bakerydemo/blob/main/bakerydemo/base/management/commands/load_initial_data.py

It should create:

• a home page with some content
• the blog overview
• some blog posts
• a couple of images for some visuals.
• ??? anything else that makes sense to include