Create open sample datasets and setup guide

[tomalrussell]

The whole stack should be possible to set up and reproduce, with open data, possibly toy examples where necessary, to demonstrate functionality and help with development.

• Hazards
• Networks
• Boundaries
• Buildings
• Damages (RP damage/loss, EAD, EAEL, adaptation)
• Land cover plus attributes, plus maritime zones, for Nature-based Solutions

These should be prepared and available in GeoPackage/parquet/TIFF formats, ready to run through the ETL pipeline to produce vector tilesets, Cloud-Optimised GeoTIFFs, and database tables.