Pause / resume sync from command line in desktop client

* Please use the 👍 [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to show that you want to have the same feature implemented.
* Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
* Subscribe to receive notifications on status change and new comments.

### Feature description
Is it possible to implement ability to pause/resume sync in desktop client from command line?
For instance:
`nextcloud --pause`
`nextcloud --resume`
It would easily make possible to create global keyboard shortcuts for that.