Job missed under heavy system load

Under high load on virtualization host a recording was missed. The APScheduler thread woke up 1.6 seconds late.

[2021-08-05 03:55:01,623] [PID 11] [APScheduler] [apscheduler.executors.default] [WARNING] Run time of job "RecordingJob.run (trigger: cron[month='*', day='*', day_of_week='2', hour='20', minute='55'], next run at: 2021-08-11 20:55:00 PDT)" was missed by 0:00:01.622979

Need to set misfire_grace_time to something higher than the default (1 second). Because the current scheduling mechanism (cron) has only 1-minute granularity anyway, a misfire_grace_time of 60 seconds should be fine.