WIP new frontend
Initial refactor: badger -> gravel
Add new PersistentObjectActions API
Add ExecuteQueryOptions
Add example config
Remove StartTime from App
move internal actions to own files
Split up database logic from Service
Rename Object to PersistentObject
fix type alias for AttributeVisibility
Add FileSystemStore for users
Remove poorly implemented hooks
Remove AuthHandler
Remove virtual attributes from example-postgres
move user code to own package
Move handlers from user_account.go to badger.go
Remove JsonUserStore
Add initial AuthHandler