add support for smart contract diagnostic events

[tsachiherman]

What

add support for smart contract debug events

How

As a result, the code calling soroban-rpc's simulateTransaction and getEvents should be updated to match the changes at stellar/stellar-cli#473 and stellar/stellar-cli#475

TODO : we need a bit deeper analysis so we can better estimate time efforts. example : how many objects would be changed, which unit tests are going to be affected.

Epic

stellar/stellar-cli#471

[2opremio]

As a result, the code calling soroban-rpc's simulateTransaction and getEvents should be updated to match the changes at stellar/stellar-cli#473 and stellar/stellar-cli#475