remove LibTorch dependencies from lidar_centerpoint

[yukke42]

LibTorch (PyTorch C++ API) is useful to deploy the models trained on PyTorch and used for the lidar_centerpoint implementation, but this library has mainly two disadvantages for autoware.

• It needs to be built for every OS and CUDA version. (https://pytorch.org/)
• It has fuge cuda libraries and they allocate more than 1GB of GPU memory, but most of them aren't used in lidar_centerpoint. (https://discuss.pytorch.org/t/pytorch-1-8-1-cu111-package-size-and-memory-usage-issue/128713)

Therefore, libtorch needs to be removed and the equivalent libraries used for lidar_centerpoint are to be reimplemented.

[yukke42]

PR is merged.