Stagger timed declarative multibranch pipeline executions in Jenkins

Jenkinsfile

// This generates a consistent, per-branch, not-really-random,
// execution time between 20:00 and 5:59 every day.

branchNum = BRANCH_NAME.inject(0) { acc, c -> acc + ((c as char) as int) }
cronHour = [20, 21, 22, 23, 0, 1, 2, 3, 4, 5][branchNum % 10]
cronMinute = branchNum % 60
cronParams = "${cronMinute} ${cronHour} * * *"

// ...

triggers { cron(cronParams) }

// ...

echo "This pipeline is scheduled to run automatically at ${cronHour}:${cronMinute} every day."