Cuda acceleration for quantized model. (#1754)

* Boilerplate for the quantized cuda support.

* More basic cuda support.

* More cuda quantization (quantize on cpu for now).

* Add the dequantization bit.

* Start adding some dedicated cuda kernels from llama.cpp.

* Move the kernel code.

* Start interfacing with the kernel.

* Tweak the kernel launch params.

* Bugfix for quantized metal.

* Fix some clippy lints.

* Tweak the launch parameters.

* Tweak cuda basics to perform a quantized matmul.

* Perform the dequantization on the cpu + use cublas for matmul.

* Add the dequantization kernel.

* Test the qmatmul.

* More kernels.

* Matmul-vec kernel.

* Add a couple kernels.

* More dequantization kernels.

candle-examples/examples/custom-ops/cuda_kernels.rs

@@ -0,0 +1 @@
+pub const LAYERNORM_KERNELS: &str = include_str!(concat!(env!("OUT_DIR"), "/layernorm_kernels.ptx"));