New chapter/content detection and notification (for bookmarked mangas)

[Sheepux]

As a daily reader
I want to be able to figure out wich manga in my bookmark has newer content
So that i can quickly browse to it and read/download it

[Sheepux]

First attempt done with #425

Issues with

• multilanguages mangas
• no limiter (might not work on some website that have limits of requests per minute)
• the new content detection itself (to be improved maybe)