enable grpc server reflection

[jdpedrie]

This PR adds support for server reflection, enabling the use of tools like grpcui.

[jnioche]

Thanks @jdpedrie
Any drawbacks in using it? I assume this won't affect performance in any way

[jdpedrie]

Not according to this stackoverflow answer. I would imagine the service would be deployed either for testing/development, or in an internal environment, but it might still make sense to place it behind a config flag.

[jnioche]

but it might still make sense to place it behind a config flag.

+1

[jdpedrie]

Done in the latest commit.

[jnioche]

thanks @jdpedrie