a way to work with most recently released cores

[city41]

Discussed in https://github.com/city41/AMMiSTer/discussions/111

^{Originally posted by matijaerceg April 20, 2023} One thing I've wished for is a way to know what has been added to the catalog since I last updated. The thing that brought me to this app is a post on Reddit showing the screenshot of newly added titles. Unfortunately, past this catalog update log, which only shows up once, there's no way for me to know, in app, what those most recently released cores are.

Does the catalog keep track of when each title was added to it? If so, can we use this info in ammister?

For example, at the very least, I'd love to be able to sort the left column by 'added' date.