Ingest ExternalReviews from K+

Adds a new entity ExternalChapterMetadata, which would allow us to
extend chapters to Recommendations, Ratings, etc in the future

API/Data/Repositories/ExternalChapterMetadataRepository.cs

@@ -0,0 +1,45 @@
+#nullable enable
+using System.Collections;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using API.Entities.Metadata;
+using API.Extensions.QueryExtensions;
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
+
+namespace API.Data.Repositories;
+
+public enum ExternalChapterMetadataIncludes
+{
+    None = 0,
+    ExternalReviews = 1 << 1,
+}
+
+public interface IExternalChapterMetadataRepository
+{
+    void Attach(ExternalChapterMetadata externalChapterMetadata);
+    void Remove(IEnumerable<ExternalChapterReview>? reviews);
+
+    Task<ExternalChapterMetadata?> Get(int chapterId, ExternalChapterMetadataIncludes includes = ExternalChapterMetadataIncludes.ExternalReviews);
+}
+
+public class ExternalChapterMetadataRepository(DataContext context, IMapper mapper): IExternalChapterMetadataRepository
+{
+
+    public void Attach(ExternalChapterMetadata externalChapterMetadata)
+    {
+        context.ExternalChapterMetadata.Attach(externalChapterMetadata);
+    }
+    public void Remove(IEnumerable<ExternalChapterReview>? reviews)
+    {
+        if (reviews == null) return;
+        context.ExternalChapterReview.RemoveRange(reviews);
+
+    }
+    public async Task<ExternalChapterMetadata?> Get(int chapterId, ExternalChapterMetadataIncludes includes = ExternalChapterMetadataIncludes.ExternalReviews)
+    {
+        return await context.ExternalChapterMetadata
+            .Includes(includes)
+            .FirstOrDefaultAsync(c => c.ChapterId == chapterId);
+    }
+}