See paritytech/polkadot#4259 for the context why util::jobs was removed.

Outdated guide page: https://paritytech.github.io/polkadot/book/node/subsystems-and-jobs.html.

https://github.com/paritytech/polkadot/blob/master/roadmap/implementers-guide/src/node/subsystems-and-jobs.md