New: Use ASP.NET Core instead of Nancy

(cherry picked from commit 58ddbcd77e17ef95ecfad4b746084ee9326116f3)

src/Prowlarr.Http/Frontend/Mappers/StaticResourceMapperBase.cs

@@ -1,7 +1,7 @@
 using System;
 using System.IO;
-using Nancy;
-using Nancy.Responses;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.StaticFiles;
 using NLog;
 using NzbDrone.Common.Disk;
 using NzbDrone.Common.EnvironmentInfo;
@@ -13,14 +13,14 @@ namespace Prowlarr.Http.Frontend.Mappers
         private readonly IDiskProvider _diskProvider;
         private readonly Logger _logger;
         private readonly StringComparison _caseSensitive;
-
-        private static readonly NotFoundResponse NotFoundResponse = new NotFoundResponse();
+        private readonly IContentTypeProvider _mimeTypeProvider;
 
         protected StaticResourceMapperBase(IDiskProvider diskProvider, Logger logger)
         {
             _diskProvider = diskProvider;
             _logger = logger;
 
+            _mimeTypeProvider = new FileExtensionContentTypeProvider();
             _caseSensitive = RuntimeInfo.IsProduction ? DiskProviderBase.PathStringComparison : StringComparison.OrdinalIgnoreCase;
         }
 
@@ -28,19 +28,23 @@ namespace Prowlarr.Http.Frontend.Mappers
 
         public abstract bool CanHandle(string resourceUrl);
 
-        public virtual Response GetResponse(string resourceUrl)
+        public virtual IActionResult GetResponse(string resourceUrl)
         {
             var filePath = Map(resourceUrl);
 
             if (_diskProvider.FileExists(filePath, _caseSensitive))
             {
-                var response = new StreamResponse(() => GetContentStream(filePath), MimeTypes.GetMimeType(filePath));
-                return new MaterialisingResponse(response);
+                if (!_mimeTypeProvider.TryGetContentType(filePath, out var contentType))
+                {
+                    contentType = "application/octet-stream";
+                }
+
+                return new FileStreamResult(GetContentStream(filePath), contentType);
             }
 
             _logger.Warn("File {0} not found", filePath);
 
-            return NotFoundResponse;
+            return null;
         }
 
         protected virtual Stream GetContentStream(string filePath)