Allow "Recently Added" to be customized per Library.

I have created a few different libraries such as Movies, Movies.4k, Movies.3D, and TV Shows.

The “Recently Added” for Movies includes all the 4k, regular and 3D movies. I’d like for Plex to show each of those libraries as separate “Recently Added”. That will allow me to know when there is new 4K movies vs just regular ones.

It would also be nice to have the ability to remove items from recently added lists. It’s a bit annoying when relocating media files (while reorganizing, or because of copying to the wrong folder) that something I’ve had for years is suddenly “Recently Added” again.

It would also be nice to set a time limit on what “recently” actually means. I went for 8 months without adding anything new and yet I still had a full list of “recently” added items. I prefer recent to have a much shorter time window.

Early 2021 clean-up: duplicate/implemented