Added manga data and pipeline.

MangaReader.Core/Data/ChapterPage.cs

@@ -0,0 +1,11 @@
+namespace MangaReader.Core.Data;
+
+public class ChapterPage
+{
+    public int ChapterPageId { get; set; }
+
+    public int MangaChapterId { get; set; }
+    public required MangaChapter MangaChapter { get; set; }
+
+    public int PageNumber { get; set; }
+}