Send log line w/ trace

[agardnerIT]

Add functionality to send a log line with the trace and span ID preset.

This means that backends should automatically be able to correlate the log line with the span.

1. Send Logs to Collector

curl -X POST http://1.2.3.4:4318/v1/logs \
-H "Content-Type: application/json" \
-d '{"resourceLogs":[{"resource":{"attributes":[{"key":"resource-attr","value":{"stringValue":"resource-attr-val-1"}}]},"scopeLogs":[{"scope":{},"logRecords":[{"timeUnixNano":"1581452773000000789","severityNumber":9,"severityText":"Info","name":"logA","body":{"stringValue":"This is a log message"},"attributes":[{"key":"app","value":{"stringValue":"server"}},{"key":"instance_num","value":{"intValue":"1"}}],"droppedAttributesCount":1,"traceId":"08040201000000000000000000000000","spanId":"0102040800000000"},{"timeUnixNano":"1581452773000000789","severityNumber":9,"severityText":"Info","name":"logB","body":{"stringValue":"something happened"},"attributes":[{"key":"customer","value":{"stringValue":"acme"}},{"key":"env","value":{"stringValue":"dev"}}],"droppedAttributesCount":1,"traceId":"","spanId":""}]}]}]}'

2. Have Collector Send Logs to Backend (eg. Loki)

From here: https://grafana.com/docs/opentelemetry/collector/send-logs-to-loki/loki-receiver/

exporters:
  loki:
    endpoint: http://loki:3100/loki/api/v1/push

service:
  pipelines:
    logs:
      receivers: [loki]
      processors: [attributes]
      exporters: [loki]

[agardnerIT]

This will now be handled by logpusher