Migrate otel metrics to use mdatagen: routing processor

[jpkrohling]

Before:

# HELP otelcol_routing_processor_non_routed_log_records Number of log records that were not routed to some or all exporters
# TYPE otelcol_routing_processor_non_routed_log_records counter
otelcol_routing_processor_non_routed_log_records{routing_key="",service_instance_id="c0c03666-9ef6-456e-ae9d-b5d8c2041ce4",service_name="otelcontribcol",service_version="0.102.0-dev"} 1
# HELP otelcol_routing_processor_non_routed_metric_points Number of metric points that were not routed to some or all exporters.
# TYPE otelcol_routing_processor_non_routed_metric_points counter
otelcol_routing_processor_non_routed_metric_points{routing_key="",service_instance_id="c0c03666-9ef6-456e-ae9d-b5d8c2041ce4",service_name="otelcontribcol",service_version="0.102.0-dev"} 1
# HELP otelcol_routing_processor_non_routed_spans Number of spans that were not routed to some or all exporters.
# TYPE otelcol_routing_processor_non_routed_spans counter
otelcol_routing_processor_non_routed_spans{routing_key="",service_instance_id="c0c03666-9ef6-456e-ae9d-b5d8c2041ce4",service_name="otelcontribcol",service_version="0.102.0-dev"} 2

After:

# HELP otelcol_routing_processor_non_routed_log_records Number of log records that were not routed to some or all exporters.
# TYPE otelcol_routing_processor_non_routed_log_records counter
otelcol_routing_processor_non_routed_log_records{routing_key="",service_instance_id="f27bc682-a3a0-44ed-9b88-b870dd4d096a",service_name="otelcontribcol",service_version="0.102.0-dev"} 1
# HELP otelcol_routing_processor_non_routed_metric_points Number of metric points that were not routed to some or all exporters.
# TYPE otelcol_routing_processor_non_routed_metric_points counter
otelcol_routing_processor_non_routed_metric_points{routing_key="",service_instance_id="f27bc682-a3a0-44ed-9b88-b870dd4d096a",service_name="otelcontribcol",service_version="0.102.0-dev"} 1
# HELP otelcol_routing_processor_non_routed_spans Number of spans that were not routed to some or all exporters.
# TYPE otelcol_routing_processor_non_routed_spans counter
otelcol_routing_processor_non_routed_spans{routing_key="",service_instance_id="f27bc682-a3a0-44ed-9b88-b870dd4d096a",service_name="otelcontribcol",service_version="0.102.0-dev"} 2

Configuration used for testing:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: localhost:4317

processors:
  routing:
    default_exporters: [ debug/routed ]
    attribute_source: resource
    from_attribute: vip
    error_mode: ignore
    table:
      - value: "true"
        exporters:
          - debug/vip

exporters:
  debug:
    verbosity: detailed
  debug/routed:
    verbosity: detailed
  debug/vip:
    verbosity: detailed

service:
  pipelines:
    traces:
      receivers: [otlp]
      processors: [routing]
      exporters: [debug, debug/routed, debug/vip]
    logs:
      receivers: [otlp]
      processors: [routing]
      exporters: [debug, debug/routed, debug/vip]
    metrics:
      receivers: [otlp]
      processors: [routing]
      exporters: [debug, debug/routed, debug/vip]

Test commands:

telemetrygen metrics --metrics 1 --otlp-insecure --otlp-attributes='vip="false"'
telemetrygen logs --logs 1 --otlp-insecure --otlp-attributes='vip="false"'
telemetrygen traces --traces 1 --otlp-insecure --otlp-attributes='vip="false"'

Fixes #33526

Signed-off-by: Juraci Paixão Kröhling juraci@kroehling.de

[codeboten]

Only one question about optional to avoid instantiating unnecessary instruments

[codeboten]

go.mod file needs resolving