[opentelemetry] Collect logs from Logshipper plugin

[timojohlo]

Context

As a alternative to receive container logs via the filelog receiver with OpenTelemetry we also want to receive container logs from the logshipper plugin that uses FluentBit as container log collector.

Acceptance criteria

• [ ] re-write Logshipper to also write logs to OTel collector (as side-car or direct)
• [ ] Receive logs in OTel collector
• [ ] Push logs from Collector to OpenSearch

References

• https://github.com/cloudoperators/greenhouse-extensions/blob/main/logshipper/plugin.yaml