Implement Jaeger SpanWriter gRPC API #3046
Description
From 0.5, Quickwit supports Jaeger SpanReader gRPC API.
It could be interesting to also support the SpanWriter gRPC API so that Quickwit can be a drop-in replacement of a span storage backend, cf Jaeger README that shows a Jaeger collector in front of the storage backend.
(raised by @yurishkuro when discussing on jaeger slack channel)