Added the ability to refresh out backend metadata (#2078)

We now can refresh the Plex Metadata in our database. For example if the Plex Agent for TV Shows is TheMovieDb, we will use that and populate the IMDB Id and TheTvDb Id's so we can accuratly match and search things.

Also improved the Job settings page so we can Test CRON's and we also validate them.

src/Ombi.Api/HttpRequestExtnesions.cs

@@ -0,0 +1,45 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace Ombi.Api
+{
+    public static class HttpRequestExtnesions
+    {
+        public static async Task<HttpRequestMessage> Clone(this HttpRequestMessage request)
+        {
+            var clone = new HttpRequestMessage(request.Method, request.RequestUri)
+            {
+                Content = await request.Content.Clone(),
+                Version = request.Version
+            };
+            foreach (KeyValuePair<string, object> prop in request.Properties)
+            {
+                clone.Properties.Add(prop);
+            }
+            foreach (KeyValuePair<string, IEnumerable<string>> header in request.Headers)
+            {
+                clone.Headers.TryAddWithoutValidation(header.Key, header.Value);
+            }
+
+            return clone;
+        }
+
+        public static async Task<HttpContent> Clone(this HttpContent content)
+        {
+            if (content == null) return null;
+
+            var ms = new MemoryStream();
+            await content.CopyToAsync(ms);
+            ms.Position = 0;
+
+            var clone = new StreamContent(ms);
+            foreach (KeyValuePair<string, IEnumerable<string>> header in content.Headers)
+            {
+                clone.Headers.Add(header.Key, header.Value);
+            }
+            return clone;
+        }
+    }
+}