[3rdparty, document] Add 3rdparty/amd, with profiling and tuning instructions to be added (#1822)

3rdparty/amd/tuning/TUNING.md

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+## Tuning SGLang Infer System with AMD GPUs
+This AppNote describes the SGLang performance tuning technical, code harness and running steps for systems with AMD Instinct GPUs.
+Harness code, examples and steps are provided in detail, to facilitate easy reproduce & use to tune performance towards workloads.
+Three primary runtime areas are covered:
+- Triton Kernels
+
+
+- Torch Tunable Ops 
+
+
+- Torch Compile
+
+