Feature Request: Re-introduce "keepDoneJobs" option to retain successful jobs #97

Description

Hello,

I had been using the dev-develop version of this package for a long time. Today, I upgraded to the latest stable release and realized that successful jobs are no longer being saved in the database. It appears that the keepDoneJobs configuration option has been removed.

I would like to request bringing this feature back or introducing a similar mechanism to retain successfully processed jobs.

Context & Use Case

I am currently using Database as my defaultHandler. Previously, the keepDoneJobs option allowed me to keep successfully completed jobs in the database rather than deleting them immediately. This was incredibly useful for observing, auditing, and debugging successful job executions over time.

Now that successful jobs are instantly purged upon completion, I have lost the ability to monitor job history directly from the database, unless I build a completely separate custom logging mechanism.

Proposed Solution

Re-add the keepDoneJobs boolean configuration (perhaps defaulting to false to maintain the current default behavior). When set to true, the Database handler should mark the jobs as done instead of deleting the records.

Thank you for your time and for the great work on this package!