NoteService should be the only class with access to NoteDao;
nowhere else should NoteDao be accessed directly.
Channel dependencies are static in PacketProcessor, for now.
Ideally they would be injected in the constructor,
but since the constructor is private and I don't want to open
up that can of worms, I'll leave it like this.
At the very least, now we have a way of injecting services into
the handlers. This will make further restructuring way easier.
- Use multi-stage build for the application image
- Utilize connection pool init timeout for waiting on database container startup,
"docker-compose-wait" dependency is no longer required
- Override database host through environment variable - used in docker-compose
- Rename database scripts for explicit ordering (db container loads them alphabetically)
