Update #42: AD Migration

Refactor to target specific Domain Controllers, with failover.

Disco.Services/Interop/ActiveDirectory/IADObject.cs

@@ -0,0 +1,18 @@
+
+using System.Security.Principal;
+namespace Disco.Services.Interop.ActiveDirectory
+{
+    public interface IADObject
+    {
+        ADDomain Domain { get; }
+
+        string DistinguishedName { get; }
+        SecurityIdentifier SecurityIdentifier { get; }
+        
+        string Id { get; }
+        string SamAccountName { get; }
+
+        string Name { get; }
+        string DisplayName { get; }
+    }
+}