Support opentelemetry logs

[cartermp]

I'd love to be able to emit data as opentelemetry logs since the data model is stable: https://opentelemetry.io/docs/reference/specification/logs/data-model/#log-and-event-record-definition

An example of what I might expect to be able to do:

# ... some stuff from http_events

px.export(
    df, px.otel.Data(
        resource={
            'service.name': df.service,
            'k8s.container.name': df.container,
            'service.instance.id': df.pod,
            'k8s.pod.name': df.pod,
            'k8s.namespace.name': df.namespace,
            'px.cluster.id': df.cluster_id,
            'k8s.cluster.name': df.cluster_name,
            'instrumentation.provider': df.pixie,
        },
        data=[
            px.otel.Log(
                # required
                timestamp=df.time_,
                # required
                severity_number=9
                # required
                severity_text='info'
                body={
                    'name': 'phillip's sweet log'
                    'parent.service.name': df.parent_service,
                    'parent.k8s.pod.name': df.parent_pod,
                    'http.method': df.req_method,
                    'http.url': df.req_url,
                    'http.target': df.req_path,
                    'http.host': df.host,
                    'http.status_code': df.resp_status,
                    'http.user_agent': df.user_agent,
                    'http.request_content_length': df.req_body_size,
                    'http.response_content_length': df.resp_body_size,
                    'http.request.header': df.req_headers,
                    'http.response.header': df.resp_headers,
                },
            ),
        ],
    ),
)

It feels like a more natural fit for http_events compared to OTel spans, since there's no (apparent) way to propagate trace info in HTTP headers.

[ddelnano]

@cartermp I know it's been a while since you opened this issue, but I'm actively working on log support. I have it fully working end to end and I'm starting to merge the changes in one by one.

It should hoepfully be available in the next few weeks.