Describe how to migrate configuration JSON & ENVs from `2.0.0-pre-rc.20` to the new configuration system introduced in https://github.com/hyperledger/iroha/pull/4239.
Describe how to migrate configuration JSON & ENVs from
2.0.0-pre-rc.20to the new configuration system introduced in hyperledger-iroha/iroha#4239.