Subscribe to events without contract

[kroggen]

Currently it is only possible to subscribe to events informing a single contract address for filter

But in some cases we are interested in many contracts, or not any specifically, but in some type of event

For these cases we could allow the subscription to events using only the event name as the filter

This allows the subscription to a type of event, regardless of which contract will emit it

This can be applied to ListEvents and ListEventStream