Solve potential bibliographic data update issues in database.py

[mhucka]

Currently, the implementation of Item in database.py includes fields for metadata like title, year, etc. These metadata fields are populated from the LSP/ILS at the time the Item object is created. The fields are used to fill out the /item page. Unfortunately, keeping this data cached introduces the problem that the metadata may be updated in the LSP but never be updated in the Item object kept in the database.

Getting the data dynamically every time /item pages are generated is not an option due to obvious performance reasons, but we should find a way to (e.g.) refresh the data, or otherwise avoid potential data inconsistencies.

[mhucka]

This is partly helped by having the new admin utility update-item-data. Running it will refresh the data from the LSP.

A problem remains that it's not something that staff can do via the web interface but instead requires staff with CLI access to the server to remember to run every once in a while.

Still, this is no longer really a bug but a question of enhancing the system. Changing this issue from a bug to an enhancement.