Add errinfo package with error types (#15300)

* Add errinfo package with error types

* rename based on feedback

sdk/internal/errorinfo/errorinfo.go

@@ -0,0 +1,15 @@
+// +build go1.13
+
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package errorinfo
+
+// NonRetriable represents a non-transient error.  This works in
+// conjunction with the retry policy, indicating that the error condition
+// is idempotent, so no retries will be attempted.
+// Use errors.As() to access this interface in the error chain.
+type NonRetriable interface {
+	error
+	NonRetriable()
+}