otel-collector: add logging exporter configuration for traces

Created by: bobheadxi

This is not the export of logs, but the export of traces as logs. This can be the default configuration as we move towards the Sourcegraph 4.0 collector-without-jaeger configuration.

Test plan

sg.config.overwrite.yaml:

commands:
  otel-collector:
    env:
      CONFIGURATION_FILE: 'configs/logging.yaml'