Object Explorer Service (#311)

* moving OE service from an old branch

src/Microsoft.SqlTools.ServiceLayer/ObjectExplorer/Nodes/ValidForFlag.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Microsoft.SqlTools.ServiceLayer.ObjectExplorer.Nodes
+{
+    /// <summary>
+    /// Indicates which type of server a given node type is valid for
+    /// </summary>
+    [Flags]
+    public enum ValidForFlag
+    {
+        Sql2005 = 0x01,
+        Sql2008 = 0x02,
+        Sql2012 = 0x04,
+        Sql2014 = 0x08,
+        Azure = 0x10,
+        NotDebugInstance = 0x20,
+        NotContainedUser = 0x40,
+        AzureV12 = 0x80,
+        Sql2016 = 0x100,
+        CanConnectToMaster = 0x200,
+        CanViewSecurity = 0x400,
+        SqlvNext = 0x800,
+        All = Sql2005 | Sql2008 | Sql2012 | Sql2014 | Sql2016 | SqlvNext | Azure | AzureV12
+    }
+}