Fused moe gemm + silu activation kernel

[Chi-Chu319]

!!Merge only after the tianxing/moe_quantization branch is merged!!

Implemented the moe gemm + silu_and_mul fusion. The logic of the fusion is:

• Load the b pointer in a interleaved manner, [0, 0 + BLOCK_N // 2, 1, 1 + BLOCK_N // 2, 3, 3 + BLOCK_N // 2, ..., BLOCK_N // 2 - 1, BLOCK_N]
• After the gemm, we can simply reshape the gemm product to (BLOCK_SIZE_M, BLOCK_SIZE_N // 2, 2) and split to obtain the silu_acc and mul_acc
• Apply silu on silu_acc and multiply it with mul_acc
• Store the result

You can benchmark the fused kernel (moe gemm + silu activation) with the -use_silu_activation flag.
Implemented a separate silu_and_mul kernel. You can benchmark the moe gemm + silu activation combo as separate kernels on triton with -use_silu_activation_non_fused flag.

The fused kernel:

Model	M	N	K	E	top_k	Time (ms)	TFLOPS	Bandwidth (GB/s)
mistral-7B	4096	14336	4096	8	2	2.363253	414.184572	462.545290
mistral-22B	4096	16384	6144	8	2	4.062578	413.183111	443.231723

moe gemm + silu activation as separate kernels:

Model	M	N	K	E	top_k	Time (ms)	TFLOPS	Bandwidth (GB/s)
mistral-7B	4096	14336	4096	8	2	2.358011	382.156425	449.828031
mistral-22B	4096	16384	6144	8	2	4.288173	386.892861	431.299634

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