CUDA/Windows instructions do not work; there is no setup.py

# Prerequisites

Please answer the following questions for yourself before submitting an issue.

- [X ] I am running the latest code. Development is very rapid so there are no tagged versions as of now.
- [ X] I carefully followed the [README.md](https://github.com/abetlen/llama-cpp-python/blob/main/README.md).
- [ X] I [searched using keywords relevant to my issue](https://docs.github.com/en/issues/tracking-your-work-with-issues/filtering-and-searching-issues-and-pull-requests) to make sure that I am creating a new issue that is not already open (or closed).
- [ X] I reviewed the [Discussions](https://github.com/abetlen/llama-cpp-python/discussions), and have a new bug or useful enhancement to share.

# Expected Behavior

I expect CUDA support to work, or not to be claimed to work.

# Current Behavior

CUDA does not work.

# Environment and Context

Win11 x64, followed all instructions. Still runs 100% CPU.

* Physical (or virtual) hardware you are using, e.g. for Linux:

`$ lscpu`

* Operating System, e.g. for Linux:

`$ uname -a`

* SDK version, e.g. for Linux:

```
$ python3 --version
$ make --version
$ g++ --version
```

# Failure Information (for bugs)

Your instructions are wrong.

# Steps to Reproduce

There is no setup.py.

Try the following:

1. `git clone https://github.com/abetlen/llama-cpp-python`
2. `cd llama-cpp-python`
3. `rm -rf _skbuild/` # delete any old builds
4. `python setup.py develop`
5. `cd ./vendor/llama.cpp`
6. Follow [llama.cpp's instructions](https://github.com/ggerganov/llama.cpp#build) to `cmake` llama.cpp
7. Run llama.cpp's `./main` with the same arguments you previously passed to llama-cpp-python and see if you can reproduce the issue. If you can, [log an issue with llama.cpp](https://github.com/ggerganov/llama.cpp/issues)

# Failure Logs

There is no setup.py. Nothing else matters because your instructions don't even match the reality of which files exist.