Situation

Currently, Graph Node configured to use a Firehose for Ethereum indexing still needs to connect to an RPC endpoint in order to ingest blocks to keep the chain head pointer up to date.

Resolution

Add a Firehose block ingestor for Ethereum, similar to the implementations for other protocols without an existing RPC setup

This should be configurable (i.e. to prefer an RPC or Firehose Block Ingestor)