CUDA full GPU acceleration, KV cache in VRAM (#1827)
* Fixed CUDA RoPE
* ggml_cuda_mul_mat_vec_p021
* ggml_cuda_scale
* ggml_cuda_diag_mask_inf
* ggml_is_permuted
* ggml_cuda_cpy
* flatten rows for ggml_cuda_op
* Added a --low-vram option
* Fixed Windows performance
* Fixed LLAMA_CUDA_DMMV_Y > 1 for WizardLM
