Add the ability to append additional log in the receipt after a post processing hook

[thomas-nguy]

After a PostTxProcessing , in some cases some informations need to passed to the users

In that case it would make sense to have to ability to add more logs to the receipt.

One concrete example:
When hooking with the gravity bridge. the function return an "id" which specify the batch your transaction has been bundled to.
This Id is essential for user if they want to cancel the operation.

With this feature, we can return a specific log that the Dapp that catch in order to implement a cancel mechanism.