[TASK] Sync the order of public inputs for R1CS and PLONK

[lazovicff]

For Mixer:

1. nullifier_hash
2. root
3. arbitrary data

For Anchor:

1. chain_id
2. nullifier_hash
3. arbitrary_data
4. roots[]

For VAnchor:

1. public_amount
2. public_chain_id
3. arbitrary_data
4. in_nullifier_hashes[]
5. in_root_set[]
6. out_commitments[]

We would have to sacrifice some of the performance to achieve this in PLONK. For example: Set gadgets expects a set to be Vec<F> which are public inputs (https://github.com/webb-tools/arkworks-gadgets/blob/master/arkworks-plonk-circuits/src/set_membership/mod.rs#L15). They are inserted into the circuit at the specific time to avoid additional gates. We would have make a standard for PLONK to give us control where the public inputs are defined, which will make it easier for make PLONK and R1CS interoperable.

[lazovicff]

Should be equal to solidity side