Consider serialising job's output with Superjson

[infomiho]

Currently, we only support job's output being plain objects with primitive values i.e. stuff that can be serialised to JSON and deserialised from JSON.

Because of that we don't support a common type like Date in the job's output. We could improve the DX by using Superjson to serialise our jobs' output.

Context: https://ptb.discord.com/channels/686873244791210014/1207604340789874719/1207776925162938528