PyTorch 2.4: Python 3.12, AOTInductor freezing, libuv backend for TCPStore

# PyTorch 2.4 Release Notes - Highlights - Tracked Regressions - Backward incompatible changes - Deprecations - New features - Improvements - Bug Fixes - Performance - Documentation - Developers - Security ## Highlights We are excited to announce the release of PyTorch® 2.4! PyTorch 2.4 adds support for the latest version of Python (3.12) for `torch.compile`. AOTInductor freezing gives developers running AOTInductor more performance based optimizations by allowing the serialization of MKLDNN weights. As well, a new default TCPStore server backend utilizing `libuv` has been introduced which should significantly reduce initialization times for users running large-scale jobs. Finally, a new Python Custom Operator API makes it easier than before to integrate custom kernels into PyTorch, especially for `torch.compile`. This release is composed of 3661 commits and 475 contributors since PyTorch 2.3. We want to sincerely thank our dedicated community for your contributions. As always, we encourage you to try these out and report any issues as we improve 2.4. More information about how to get started with the PyTorch 2-series can be found at our [Getting Started](https://pytorch.org/get...