Create MS.SqlTools.Credentials project (#249)

* Initial credential service files

* Clean-up hostloader

* Update build scripts to build credentials archive

* Move hosting files to new assembly

* Add credentials files to MS.SqlTools.Credentials

* Remove duplicate files

* Update namespace in program.cs

* Fix test build breaks

* Update extensions visibility.

* Remove unused resource strings

* Add xproj files to SLN for appveyor builds

* Fix appveyor build break in test project

* Fix extensibility tests

* Fix various typos in latest iteration

* Add settings for Integration build

* Fix codecoverage.bat to use full pdb for new projects

* Fix bug when packing in folder with native images

* Fix typos in xproj

* Reset XLF to fix build.cmd

src/Microsoft.SqlTools.Credentials/Program.cs

@@ -0,0 +1,47 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using Microsoft.SqlTools.Credentials.Utility;
+using Microsoft.SqlTools.ServiceLayer.Hosting;
+using Microsoft.SqlTools.ServiceLayer.SqlContext;
+using Microsoft.SqlTools.ServiceLayer.Utility;
+
+namespace Microsoft.SqlTools.Credentials
+{
+    /// <summary>
+    /// Main application class for Credentials Service Host executable
+    /// </summary>
+    internal class Program
+    {
+        /// <summary>
+        /// Main entry point into the Credentials Service Host
+        /// </summary>
+        internal static void Main(string[] args)
+        {
+            // read command-line arguments
+            CommandOptions commandOptions = new CommandOptions(args);
+            if (commandOptions.ShouldExit)
+            {
+                return;
+            }
+
+            // turn on Verbose logging during early development
+            // we need to switch to Normal when preparing for public preview
+            Logger.Initialize(minimumLogLevel: LogLevel.Verbose, isEnabled: commandOptions.EnableLogging);
+            Logger.Write(LogLevel.Normal, "Starting SqlTools Credentials Provider");
+
+            // set up the host details and profile paths 
+            var hostDetails = new HostDetails(
+                name: "SqlTools Credentials Provider",
+                profileId: "Microsoft.SqlTools.Credentials",
+                version: new Version(1, 0));
+            
+            SqlToolsContext sqlToolsContext = new SqlToolsContext(hostDetails);
+            ServiceHost serviceHost = HostLoader.CreateAndStartServiceHost(sqlToolsContext);
+
+            serviceHost.WaitForExit();
+        }
+    }
+}