Scheduled jobs do not keep configured execution time

When scheduling a LogCleanupCommand with NextRun=1d, the actual execution time for the next run is calculated as (current command execution time + nextRun value). Over time, this can lead to the scheduled execution time to slip, ie. a job scheduled initially at 00:00 gets executed at 00:10, and the execution could be outside of a designated maintenance window.

The expectation is that subsequent executions happen at the defined start time + nextRun value, ie. a job scheduled initially at 00:00 with NextRun=1d should always run at 00:00, regardless of how long it takes to execute it.

Community issue tracker: https://github.com/IBM/kie-roadmap/issues/119