Add searchable timestamp field that shows when an item and/or related data was last changed

[wagn0033]

Can we get a timestamp field for items that is updated whenever the item, its subcomponents, its containers, or its tests is changed? And then, can we get an API endpoint that allows us to search for all items whose last edit was after a given date/time?

This would be used to allow a user to store large amounts of item data (to perhaps search through its specs for something) and keep it synced with the HWDB by only refreshing things that are newer than the last download.