Add ranobe field to API v1 favourites endpoint

[N0D4N]

Currently Shikimori API v1 doesn't return user's favourite ranobe when requesting /users/id/favourites endpoint. However ranobe are displayed in user's profile favourite page e.g. https://shikimori.one/N0D4N/favorites . Moreover, favourite ranobes aren't present anywhere in returned from API v1 json, even in favourite manga field.