Add github CI pipeline for Windows

[pfxuan]

Now we can natively build OpenSplat across different windows versions with latest or old cuda/libtorch stacks. This PR will activate the following builds and tests automatically. To speedup the build speed, cuda and libtorch deps caching have been seamlessly integrated into CI pipeline 🚀.

Build Matrix:

• windows-2019-cuda-11.8.0-libtorch-2.1.2
• windows-2019-cuda-12.1.1-libtorch-2.1.2
• windows-2019-cuda-11.8.0-libtorch-2.2.1
• windows-2019-cuda-12.1.1-libtorch-2.2.1
• windows-2022-cuda-11.8.0-libtorch-2.1.2
• windows-2022-cuda-12.1.1-libtorch-2.1.2
• windows-2022-cuda-11.8.0-libtorch-2.2.1
• windows-2022-cuda-12.1.1-libtorch-2.2.1

[pierotofy]

Thanks @pfxuan ! This is a great addition. 👍