Adding sr.strings file and removing hard-coded strings (#52)

* Strings sweep for connection service

* String sweep for credentials service

* String sweep for hosting

* String sweep for query execution service

* String sweep for Workspace service

* Renaming utility namespace to match standards

Renaming Microsoft.SqlTools.EditorServices.Utility to
Microsoft.SqlTools.ServiceLayer.Utility to match the naming changes done a
while back. Also renaming them on the files that use them

* Namespace change on reliable connection

* Adding the new resx and designer files

* Final bug fixes for srgen

Fixing flakey moq package name

* Removing todo as per @kevcunnane

* Adding using statements as per @llali's comment

* Fixing issues from broken unit tests

Note: This feature contains changes that will break the contract for
saving as CSV and JSON. On success, null is returned as a message instead
of "Success". Changes will be made to the vscode component to handle this
change.

test/Microsoft.SqlTools.ServiceLayer.Test/QueryExecution/ExecuteTests.cs

@@ -229,7 +229,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.QueryExecution
             // ... I create a query that has a null query text
             // Then:
             // ... It should throw an exception
-            Assert.Throws<ArgumentNullException>(() =>
+            Assert.Throws<ArgumentException>(() =>
                 new Query(null, Common.CreateTestConnectionInfo(null, false), new QueryExecutionSettings(), Common.GetFileStreamFactory()));
         }