Config option to ignore missing services (#658)

* Implemented config option to ignore missing services

* Removed unused using statement

* Resolved comments from review

Ryujinx.HLE/HOS/Services/DummyService.cs

@@ -0,0 +1,20 @@
+using Ryujinx.HLE.HOS.Ipc;
+using System.Collections.Generic;
+
+namespace Ryujinx.HLE.HOS.Services
+{
+    class DummyService : IpcService
+    {
+        private Dictionary<int, ServiceProcessRequest> _commands;
+
+        public override IReadOnlyDictionary<int, ServiceProcessRequest> Commands => _commands;
+
+        public string ServiceName { get; set; }
+
+        public DummyService(string serviceName)
+        {
+            _commands = new Dictionary<int, ServiceProcessRequest>();
+            ServiceName = serviceName;
+        }
+    }
+}