Performance Improvements (#568)

* Refactored the performance of GetChapter/BookInfo API to have a 10x speed improvement and to use common code, rather than duplicating code. Removed an api param that is no longer needed.

* Book reader now has dedicated buttons to jump to next/prev chapter as well as through page buttons

API/Interfaces/Repositories/IChapterRepository.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using API.DTOs.Reader;
 using API.Entities;
 
 namespace API.Interfaces.Repositories
@@ -8,5 +9,6 @@ namespace API.Interfaces.Repositories
     {
         void Update(Chapter chapter);
         Task<IEnumerable<Chapter>> GetChaptersByIdsAsync(IList<int> chapterIds);
+        Task<IChapterInfoDto> GetChapterInfoDtoAsync(int chapterId);
     }
 }