hoist out an otlp-protocol option that lets the caller tune what the collector listens on. this'll remove the hardcoded http endpoint in it's place, and also surface a few more usable env vars the clients can then use to connect to their desired endpoint:

• OTEL_EXPORTER_OTLP_PROTOCOL — http/protobuf or grpc
• OTEL_EXPORTER_OTLP_ENDPOINT — protocol-appropriate endpoint (4318 for HTTP, 4317 for gRPC)
• OTEL_EXPORTER_OTLP_GRPC_ENDPOINT — always localhost:4317
• OTEL_EXPORTER_OTLP_HTTP_ENDPOINT — always http://localhost:4318