Added events after cronjob finishes

[indykoning]

Description (*)

These events will allow people to hook into more cron job events than cron_job_run

When combined this will allow modules to report cron job statuses, durations, perform additional logic in case of a cron job failing vs not failing, implement cron checkins including live success/failure

Manual testing scenarios (*)

1. create observers for the added events
2. Run the cron and see the observers being triggered.

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

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[kandy]

You probably can archive the same by plugin on $schedule->save() method