Ort openvino npu 1.18.0 doc (#20707)
### Description
-These changes reflect the latest changes we have made to enable NPU
-Export OpenVINO Blob to ONNX Operator
-Enable QDQ Optimizations Passes
- Separate Device/Precision
### Motivation and Context
These changes reflect the latest changes we have made to enable NPU.
These changes reflect the latest changes we have made to enable rel-1.18
- If it fixes an open issue, please link to the issue here. -->
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Co-authored-by: Preetha Veeramalai <preetha.veeramalai@intel.com>
