[Enhancement] Show in search window if manga is already in library

[db-2001]

Not sure if this needs a change on the API side or if it can be hacked together on the website side. If it can be done on the website side, I'll take care of it. Would look like a small green check mark in the corner if a particular manga is already in the library.

[C9Glax]

Could be done on the website-side (would work similarly to the search feature on the top right).
But could also be done on api-side. Whichever way you want to do it 👍🏼

[db-2001]

I'll give it a go on the website side, I think the things I want to focus on once the Manga Hover PR gets merged in is showing the latest chapter, even if the API isn't quite there yet. Can just set the CSS display style to none until the API is ready for it.