Revert "Introduce goroutine package to campaigns background jobs (#15101)"
Created by: daxmc99
This reverts commit 25e28734563c89a6b387e755f33dfffff0751088.
This was found to prevent the repo-updater pod from starting.
It ended up not making progress past https://github.com/sourcegraph/sourcegraph/blob/25e28734563c89a6b387e755f33dfffff0751088/enterprise/cmd/repo-updater/main.go#L54 due to this change.