occ command for refreshing Calendar subscriptions

[akhil1508]

• Currently calendar subscriptions are refreshed with QueuedJobs from https://github.com/nextcloud/server/blob/master/apps/dav/lib/BackgroundJob/RefreshWebcalJob.php
• Every new subscription has a new QueuedJob added to the JobList
• For some of the bigger subscriptions, this takes many many hours to run(longest was running for 8 hours 😭 )
• Would be great to have an occ command to refresh the subscriptions so that we can optionally separate it from the NC cron
  • Something like ExpireTrash background job and occ trashbin:expire

[akhil1508]

I'd love to develop the changes for this if someone experienced with dav can tell me if it's feasible/doable.
My idea is to:

• have a setting to switch it between cron and occ
• If this is set to "occ", just return in the background job class code and
  • Get the arguments from the bg job and execute similarly in a command one by one

[joshtrichards]

Duplicate of #30294