Improve filters (my books, browse, ...)

[nikoru]

I would love to be able to filter by number of pages.

See Frontend Development Roadmap - #29 by HopeWaterfall

[Megumin]

Somewhat related:

More flexible filtering in browse & my books

Description of your request or bug report: Sometimes you can only search for certain things in browse or my books, when it seems more reasonable that you should be able to search using either of them. There are also some filters that include certain items, but cannot exclude them. Examples: In browse, I use several filters to look for a specific type of book. I then want to see which of these are in my library, but I can’t - I can only exclude my personal library. So I have to go to my book…