Support ingesting OpenTelemetry logs

[jszwedko]

Subtasks:

• Support gRPC from the OpenTelemetry collector (feat(sources): opentelemetry log #13320)
• Support HTTP (binary-encoded Protobuf format) from the OpenTelemetry collector
• Integration tests

[spencergilbert]

I had proposed we build an axum server that handles both the gRPC and HTTP requests, but we're going to punt on that for now (possibly reconsidering down the line).

Related:

• Unsplit the OTLP receiver protocols, use a shared port open-telemetry/opentelemetry-collector#1256
• Change OTLP/HTTP port from 4317 to 4318 open-telemetry/opentelemetry-specification#1839
• [PROTOTYPE] Combine gRPC and HTTP servers open-telemetry/opentelemetry-collector#3765
• Implement gRPC deframing directly on HTTP receiver port. open-telemetry/opentelemetry-collector#5067
• https://github.com/DataDog/datadog-agent/blob/main/pkg/config/config_template.yaml#L3166-L3195