Refactor and improve etheno support to be more useful

[ggrieco-tob]

This PR changes the way that etheno is used to mirror the behavior of dev-auto (which will be deprecated soon). Changes introduced:

1. Etheno mode now supports block mining event.
2. Etheno mode no longer requires to have an initialization without reverts.
3. The contract with the properties is always deployed before starting the fuzzing campaign (so detection of the contract with properties is no longer necessary).
4. After the initialization is parse, the list of transactions is added to the corpus (minus the CREATE).