Refactor the project

Update deps
Move config files to better locations
Use Hateoas 2.0
Configure Hateoas
Add cache directory
Fix bootstrap script
Use SQLite
Use Stack PHP: StackNegotiation
Remove generic controller, and introduce a DocumentController
Add a better/real Model layer
Add a View layer (Handler)
Lazy loading of translations based on the `Accept-Language` header
Add an Error class to format errors