Added user to export call

fixes #2612
- added user to db.exportContent()
Merge pull request #2615 from sebgie/issue#2612

Added user to export call
Post response move pagination -> meta

closes #2604
- moved ‚pagination‘ to ‚meta‘ property
- added response test for pagination property
- changed ‚next‘ and ‚prev‘ to be set to null and exist on every
response
- removed unnecessary call to API for RSS author
Merge pull request #2617 from sebgie/issue#2604

Post response move pagination -> meta