Allow calling cron jobs background job class with occ

[juliusknorr]

This would allow important jobs to be handled in a separate cronjob execution, so they can get executed, even if other jobs have lined up before

e.g. have a separate cron job with php occ background-job:worker OCA\\Files\\BackgroundJob\\ScanFiles

[juliusknorr]

Might be something related to #29204 to have also an occ command to run individual job classes in addition to the list. This would be similar to how Laravel handles queues https://laravel.com/docs/8.x/queues some further things to think about:

• group multiple classes by their domain/importance
• have a worker occ command that could be setup as a continuous runner

[solracsf]

This can also help in this cases: #30273

[PVince81]

we already have background-job:execute but I heard it doesn't work for all types and requires a job id, not a class name

[juliusknorr]

Sounds like a good idea to rather implement it as an occ which people could still setup as a cron job then.

[come-nc]

What does this do?

[skjnldsv]

Still stale @julien-nc ?
Please adjust labels :)

[juliusknorr]

Thanks @marcelklehr and @julien-nc for picking this one up. 🚀

[nickvergessen]

@juliushaertl Please document in https://docs.nextcloud.com/server/latest/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_30.html#id1