Abstracted & unified indexer config logic (logins are now saved), implemented indexer config migrations, fixed nCore implementation

src/Jackett/Models/IndexerConfig/ConfigurationDataBasicLogin.cs

@@ -0,0 +1,23 @@
+using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Jackett.Models.IndexerConfig
+{
+    public class ConfigurationDataBasicLogin : ConfigurationData
+    {
+        public StringItem Username { get; private set; }
+        public StringItem Password { get; private set; }
+
+        public ConfigurationDataBasicLogin()
+        {
+            Username = new StringItem { Name = "Username" };
+            Password = new StringItem { Name = "Password" };
+        }
+
+
+    }
+}