Add evaluation code for WOSAC

[zzx9636]

Add eval code for WOSAC benchmark.

Prerequisite

pip install --no-deps waymo-open-dataset-tf-2-12-0==1.6.4
pip install --no-deps git+https://github.com/waymo-research/waymax.git@main#egg=waymo-waymax

Then extract TF example from raw waymo TF example dataset using

python extract_dataset.py --data_dir XXXX --save_dir xxxx --dataset [train/val/val_interactive]

Run eval with

python examples/eval/run_wosac_eval.py