Invalid json from http endpoints

[JeroenVinke]

Hi,

When using the HTTP endpoints (--http-enabled flag) and calling the /v1/relationships/read endpoint, it will return invalid json when multiple relations are returned.

I would have expected an array of some kind with comma seperated objects. I think other endpoints may have the same problem.

[josephschorr]

Streaming endpoints do not return JSON: they return JSONL (https://jsonlines.org/), which has a JSON object per line. This is the expected format returned by the REST gateway for streaming gRPC APIs