New feature: Show the recurring tasks / cron jobs list

[lf-novelt]

Is your feature request related to a problem? Please describe.
It's easy to query the list of recurring / cron jobs for a celery beat instance, and would be useful to show it in the flower dashboard

Describe the solution you'd like
Have a new main tab, with title "Recurring jobs" (to not confuse with Scheduled tasks) that shows the list of registered cron jobs, potentially with info / link to last execution task

here is the query to get the list of registered cron jobs / beat schedules:

        """Check registered Beat schedules."""
        schedule = celery_app.conf.beat_schedule
        return {
            "scheduled_tasks": list(schedule.keys()),
            "schedules": {
                name: {
                    "task": entry["task"],
                    "schedule": str(entry["schedule"]),
                }
                for name, entry in schedule.items()
            }
        }

Inspiration:

Hangfire dashboard UI

[lf-novelt]

the raw beat config is already available in the Worker > Config page
but it does not really some useful stuff like last execution, next execution time, last result, ...