[libc++] Release libc++ for Windows (including std modules)

Currently libc++ is not being packaged for the Windows release, and with the recent changes in libc++ the C++23 standard modules are also working and compiling successfully so it possible to release them too.

Steps required:
- Package the libc++ library (static and dynamic).
- Package the libc++ standard modules files:
- `build/lib/libc++.modules.json` to `LLVM/lib/libc++.modules.json`
- `build/modules/c++/v1` to `LLVM/share/libc++/v1`

NOTE: the location of `libc++.modules.json` is important so that both the compiler and the build systems can discover it, trunk CMake can already discover it last time I tested it.

Thank you.

Review the Windows release packaging flow and trace how libc++ artifacts are placed under LLVM/lib and LLVM/share. Ensure static and dynamic libc++ libraries are packaged, along with build/lib/libc++.modules.json at LLVM/lib/libc++.modules.json and build/modules/c++/v1 at LLVM/share/libc++/v1; verify the resulting locations are discoverable by the compiler and build systems.

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