XEvent Profiler initial event handlers (#456)

* Bump SMO to 140.2.5 to pick-up private XEvent binaries

* Pick up SMO binaries from the build lab

* Add ProfilerService class placeholder

* Update SMO nuget package to include DB Scoped XEvents

* Stage changes

* Stage changes

* Update SMO to use RTM dependencies and remove separate SqlScript package

* Stage changes

* Iterate on profiler service

* Fix post-merge break in localization

* More refactoring

* Continue iterating on profiler

* Add test profiler listener

* Address a couple of the code review feedback

* Fix AppVeyor build break

* Use self-cleaning test file

src/Microsoft.SqlTools.ServiceLayer/Profiler/IXEventSession.cs

@@ -0,0 +1,18 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.ServiceLayer.Profiler
+{
+    /// <summary>
+    /// Main class for Profiler Service functionality
+    /// </summary>
+    public interface IXEventSession
+    {
+        /// <summary>
+        /// Reads XEvent XML from the default session target
+        /// </summary>
+        string GetTargetXml();
+    }
+}