Add a command to show info about a background job and force-execute it

[nickvergessen]

occ background:job 64 --force-execute Job class: OCA\Files_Retention\BackgroundJob\RetentionJob
Arguments: {"tag":2}
Type: timed
Last checked: 1970-01-01T00:00:00+00:00
Reserved at: -
Last executed: 2021-05-28T12:57:12+00:00
Last duration: 0
Next execution: 2021-05-29T12:57:12+00:00
Forcing execution of the job
Job executed!
Job class: OCA\Files_Retention\BackgroundJob\RetentionJob
Arguments: {"tag":2}
Type: timed
Last checked: 1970-01-01T00:00:00+00:00
Reserved at: -
Last executed: 2021-05-28T12:57:23+00:00
Last duration: 1
Next execution: 2021-05-29T12:57:23+00:00

The second job info is only printed for "timed" jobs that are not deleted while being executed.

[ChristophWurst]

I like the command, but the implementation feels a bit fragile 🙈

can we leave any job list related responsibility in the job list code and only fetch/invoke the job from the new command?

[MichaIng]

This is great, I was always looking for such a feature. Would it be possible to add some kind of list command to list all registered background jobs, theirs IDs, schedule, last execution etc, e.g. in a table-ish print? But that's better an own PR.

[nickvergessen]

Rebased cleanly and adjusted since versions to 23

[nickvergessen]

Rebased and bumped autoloader