Handle ndjson streaming response from /routing/v1/providers/<cid>

[masih]

Indexstar uses a delegated translator to utilise the same lookup backend for both IPNI and IPFS delegated routing apis. IPNI APIs have supported streaming response for a while now but this has not been ported over to the translator.

Update the translator such that it handles the streaming of results just like it does for IPNI APIs. This should be mostly gluecode as the code streaming functionality is already present in the backend.