doc: need docs to elaborate on oracleInfo for addWhitelistToken

[adu-web3]

Description

When the contract owner calls addWhitelistToken, it needs to pass in the oracle info, which is a string, which is constructed by joining at least three params needed with ,. We need to add doc to tell the caller how to construct valid oracle info string to avoid the oracle info being invalid

[adu-web3]

maybe we should even use struct, instead of a string, to represent oracle info, so that it would be easier to construct this param. @MaxMustermann2 what do you think?