feat: Use zerokit by default/deploy on test fleet

[fryorcraken]

Problem

The Kilic and zerokit RLN implementations are not compatible.

In go-waku, we know use zerokit by default
In the browser (js-waku+js-rln) we can only use zerokit

Which means that browser example such as https://examples.waku.org/rln-js do not work when connecting to the Waku v2 test fleet as kilic is deployed

Suggested solution

1. Deploy nwaku with zerokit on waku v2 test (and prod for next release)
2. make RLN=true compile with zerokit by default

[rymnc]

2. has been resolved by chore(Makefile): Make zerokit the default RLN implementation #1190

We can deploy the changes to the test fleet, after the contracts have been redeployed, right?
cc: @s1fr0 @staheri14

[rymnc]

Zerokit has been added to the test fleet and deployed to wakuv2.test at the moment. It will be deployed to wakuv2.prod with the next release.