Clean up error handling for frontend

[wstrm]

The error handling is horrible right now.

The backend sometimes just returns the internal error to the frontend.

I'm not sure how, but we should try to make it more DRY - maybe just let the handler return a error and have some kind of wrapper that takes care of logging and returning a cleaned up error to the front end?

I'd also like to use my own library, github.com/willeponken/causerr, just because 🙄

... Ummm, we should probably wait with this though until we got most logic working 😭

[Hjortsberg]

Hmm yes, whilst it is good to have nice error messages, this sounds a bit like premature optimization to me.
Do it, only IF time is available OR necessary! 💃

[wstrm]

We're fixin' this l8or!!! On hold.