ONNX RT-GenAI integration into LLM

* Add ONNX RT-GenAI backend (v0.8.2) support to LLM
* Build ONNX Runtime (v1.22.0) as part of ONNX Runtime-GenAI Integration
* Introduce general KleidiAI flag (-DUSE_KLEIDIAI) and configure framework-specific KleidiAI flags
* Update README with ONNX Runtime-GenAI backend usage and build instructions
* Disable -DLLAMA_CURL by default

Change-Id: I6812a3fafb78f55043a7653c7dce267a20670cf3
Signed-off-by: Yunus Kalkan <yunus.kalkan@arm.com>