add hnsw

internal/core/bench/CMakeLists.txt

internal/core/bench/bench_utils/parameter_tuning_utils.h

internal/core/bench/bench_utils/sift.h

internal/core/bench/parameter-tuning/Plots.ipynb

internal/core/bench/parameter-tuning/Plots_Search.ipynb

internal/core/bench/parameter-tuning/TODO_TUN_GET_CSV.sh

internal/core/bench/parameter-tuning/bench_flat.cpp

internal/core/bench/parameter-tuning/bench_hnsw.cpp

internal/core/bench/parameter-tuning/bench_ivfflat.cpp

internal/core/bench/parameter-tuning/bench_ivfpq.cpp

internal/core/bench/parameter-tuning/bench_ivfsq8.cpp

internal/core/src/index/unittest/test_hnsw.cpp