Extend Poseidon2 Chip for MULTI_OBSERVE

[darth-cy]

Create a new specialized chip extension to handle multiple observation into the transcript in one instruction MULTI_OBSERVE.

[kunxian-xia]

I think it's more reasonable to reuse NativePoseidon2Chip for the new added opcode. Here are the reasons:

1. we can reuse the Poseidon2SubCols columns (it has 299 columns which account for 75% of columns in NativePoseidon2Chip);

[kunxian-xia]

LGTM!