Rust and C++ - Can we remove gRPC dependency on exporter?

[austinlparker]

In Rust and C++, we have hard requirements on gRPC due to OTLP exporters even if we aren't using gRPC export. Can this be changed upstream?

[austinlparker]

open-telemetry/opentelemetry-cpp#1826

This might fix the C++ issue

[svrnm]

For c++ the exporter is not the problem alone, as far as I see it: the service itself serves via gRPC, so also that needs to be refactored.

[styblope]

Same as above for Rust + http exporter currently only supports traces, no metrics (in case we'd like to implement some)

[cartersocha]

Probably a moot point with build times reduced. Closing for now.