In case there is no middleware, trigger callback still
Implement getOne

Also discovered the middleware implementation is still a bit broken.
Sketch out middleware implementation further

Not problematic, though. Inner queries fail (they should trigger
middleware). Need to figure out how to achieve this without running into
a recursion trap again. Perhaps it is possible to skip executing
middleware for  ~just~ queries within middleware code somehow.

Perhaps there needs some kind of a stack (keeps track of inner queries).