Add Whisper VitisAI recipes

[NiranjanRaviGit]

• Adds VitisAI NPU recipes for running OpenAI Whisper small, medium, and large-v3-turbo.
• Enables Whisper encoder execution through ONNX Runtime VitisAI EP with WinML provider registration.
• Provides end-to-end speech-to-text inference scripts using local WAV input and Whisper decoding.
• Includes setup instructions for required Windows App SDK, ONNX encoder model, and VitisAI cache files.
• Adds model-specific configuration and sample audio to help users run the recipes.
• Preserves OpenAI Whisper MIT license attribution for the reused Whisper components.

[NiranjanRaviGit]

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