[Kernel] Expand MoE weight loading + Add Fused Marlin MoE Kernel (#7527)

Co-authored-by: ElizaWszola <eliza@neuralmagic.com>

csrc/moe/marlin_moe_ops.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <torch/all.h>
+
+torch::Tensor marlin_gemm_moe(
+    const torch::Tensor& a, const torch::Tensor& b_q_weights,
+    const torch::Tensor& sorted_ids, const torch::Tensor& topk_weights,
+    const torch::Tensor& topk_ids, const torch::Tensor& b_scales,
+    const torch::Tensor& g_idx, const torch::Tensor& perm,
+    torch::Tensor& workspace, int64_t size_m, int64_t size_n, int64_t size_k,
+    bool is_k_full, int64_t num_experts, int64_t topk, int64_t moe_block_size,
+    bool replicate_input, bool apply_weights);