[Issue]: support Megamoe

[Yaowu-Xiong]

Fused dispatch + L1 + SwiGLU + L2 + combine. Implement the host and the kernel part of dispatch.

[Yaowu-Xiong]

update 6/30:
1、The MegaMoE operator code has been completed along with accuracy validation.
2、Performance still needs further optimization.

[Yaowu-Xiong]

update 7/21:
megamoe_stage1
1、bs < 512, do not cache weights, improve 5% performance.
2、 deduplicating tokens during dispatch, improve 3% performance.