File storage / file system

[website-features]

I would like:

• To be able to store large files in SpacetimeDB
• I would like files to have lower prices than database memory
• Files to be stored in tables.
• To be able organize files for my database into a folder structure
• Files to be stored in a CDN for efficient reads from clients
• Access control to be implemented with reducers and views

Requested by @cloutiertyler via the SpacetimeDB site.