Fixes#45284
Some simple pagination for the library visitor console to stop it from hanging the server by trying to retrieve too much data.
The UI hasn't been made any better, I just wanted to stop us needing #49065 to be testmerged indefinitely. I went into this thinking I'd improve the UI and code but that was before I had read any of it and lost my motivation.
Bonus points for this code having allowed unsanitized arbitrary queries for at least 10 years.
2fe48855c8