Feature request: file activity export on demand

[jasonbayton]

Context: https://help.nextcloud.com/t/is-it-possible-to-export-activity-on-demand/5598

It'd be very useful for reporting/audit purposes to be able to export the activity of a file. Currently it's possible to see what has happened (uploaded, downloaded, shared) when clicking on the file within the web interface:

But aside from occasional activity emails which don't provide the full activity every email, copying and pasting from that area in the UI is the only option.

[nickvergessen]

Activity app => https://github.com/nextcloud/activity/issues