Investigate JSON RPC streaming

[AbdelStark]

Instead of creating a jackson object for an entire array of results and then serializing it, huge queries like range-based eth_getLogs would benefit from being able to be streamed.

We would need to manually write the beginning of the json array and the interspersing separators. We would create jackson objects for each result that would rely on the jackson serialization.

Maybe we can do something like this in reverse?
https://www.nurkiewicz.com/2017/09/streaming-large-json-file-with-jackson.html

[RatanRSur]

would help with #944

[macfarla]

Fixed in #3076