feat: interop tests with rln

[weboko]

This is a feature request

Problem

We do not have any interop tests with rln.

Proposed Solutions

Add tests to cover basic use cases, data structures.

[weboko]

cc: @rymnc for more details

[rymnc]

Thanks for the issue @weboko!
We need to test 1 thing initially, if proofs generated by rln-wasm are able to be verified by the rln verifier, and vice versa (due to usize encoding).

ref: vacp2p/zerokit#153 (to avoid issues like this)

[weboko]

Ice boxing for now as we might go with more light weight way for RLN.