Add SUPPORT.md (#26718)

### Description
Adding SUPPORT.md file to clarify Microsoft support policy for the
project.

Author: jaholme

SUPPORT.md

@@ -0,0 +1,13 @@
+# Support
+
+## How to file issues and get help
+
+This project uses [GitHub Issues](https://github.com/Microsoft/onnxruntime/issues) to track bugs and feature requests. Please search the existing
+issues before filing new issues to avoid duplicates.  For new issues, file your bug or
+feature request as a new Issue.
+
+For help and questions about using this project, please use [GitHub Discussions](https://github.com/microsoft/onnxruntime/discussions).
+
+## Microsoft Support Policy
+
+Support for this project is limited to the resources listed above.