[Enhancement] Allow setting "store metadata with items" on a per library basis

[advplyr]

Discussed in https://github.com/advplyr/audiobookshelf/discussions/3051

^{Originally posted by SAS-1 June 9, 2024} Hi

Currently we have an all or nothing setting to either store metadata with each item or in the metadata/items folder.

I was wondering if we could get a setting per library.

For example I would want to store the metadata in the items folder for the Ebooks as Calibre doesn't like additional files in the books folders but store the metadata with the audiobook items for my audio libraries.

Also I am working on a PowerShell to manage my metadata, am I right in saying that the JSON needs to be called metadata.json I couldn't store a copy with the audiobooks as say booktitle.json and it would read the details? When I did a quick test this seemed to be the case.

Thanks