Notification trigger option when a new book is added

[abs-borts]

Please verify that this feature request has NOT been suggested before.

• I checked and didn't find a similar feature request.

Feature Request Type

Notifications

Feature description

When Absulli notices that a new book has been added, trigger a notification to the elected notification provider

Solution

Add another notification category which fires when a new book is detected

Alternatives

This could alternatively be an ABS-native notification, but has yet to be added there (though it has been requested, surprisingly recently: advplyr/audiobookshelf#4982 )

Similarly, and perhaps worthy of its own feature request, a digest-style "books that have been added in the past week" notification or email might be a good option to cut down on the signal-to-noise ratio with busy ABS libraries

Additional Context

Initially broached the idea on the Absulli-specific thread in the "3rd-party" channel on the ABS discord

[operationETH]

Pushed a update to the nightly branch for this. I'll close it when it gets pushed to main.