Added OTLP Access logs for the frontend proxy

[martinjt]

Changes

This adds an access_log filter that sends Access Logs from the Frontend Proxy as logs to the collector.

I've tried to keep as close to the semantic conventions as I could for them. I've used Span/Trace semantics for things that made sense.

Merge Requirements

For new features contributions, please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[julianocosta89]

@martinjt could you check the failing checks and update the branch?

[julianocosta89]

@martinjt when testing it out, I've noticed that the logs have TraceID, but no SpanID.
Is that expected?

[puckpuck]

Closing this in favor of #1768