Add support for failed transactions

Do you want to request a feature or report a bug?
Feature

What is the current behavior?
Transactions do not support the status flag from receipts, nor do they support the error reason (gas or revert reason). Moreover only successful call transactions will invoke a subgraph's handlers.

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem.

What is the expected behavior?
That a failed transaction from an invocation of a call handler would:
a) Trigger the call handler in the subgraph
b) That the EthereumTransaction class would contain the following:
* a flag for status reflecting the success status of the transaction
* an errorType - reverted or out-of-gas (others?)
* the revertReason if any (which is easy to surface in ethers and web3)

The main motivation for something like this is for projects, such as ours, to track errors users have when interacting with our contracts (for monitoring tools). As users pay gas even for failed transactions, it's critical to minimize these where possible. It's even more important when they call our functions from their own contracts. As you can imagine, these calls are harder to track as unlike regular transactions invoking our contracts directly (where we are the to destination of the transaction) - their to destination is their contract which is calling ours by reference in the code.

La issue nomina la classe EthereumTransaction e gli handler delle chiamate subgraph, ma non indica file del repository né test. Inizia tracciando come vengono elaborati i receipts e gli handler delle chiamate, quindi determina come devono essere rappresentate e distribuite le transazioni fallite. Il lavoro è completato quando le chiamate fallite attivano gli handler ed espongono lo stato, il tipo di errore e un eventuale motivo di revert.