Add protocol span export scripts to OTel plugin

[ddelnano]

This PR replicates the New Relic protocol span export scripts to the OTel plugin. The HTTP spans export script will be used by my Kubecon talk where I use the resulting OTLP data to configure Envoy authZ.

The following changes were made to each script:

• Each script had its description modified (was New Relic focused) and any New Relic related comments removed.
• HTTP script was modified slightly since I found the attributes a little confusing. The diff below shows the original version against the version added here

diff

$ diff orig_http_spans.yaml http_spans.yaml
67,74c67,71
<       # While other Pixie entities use `service.name=source_service`,
<       # the Services-OpenTelemetry entity is set up to only show clients so we use `service.name=destination_service`.
<       'service.name': df.destination_service,
<       'service.instance.id': df.destination_pod,
<       'k8s.pod.name': df.destination_pod,
<       'k8s.deployment.name': df.destination_deployment,
<       'k8s.namespace.name': df.destination_namespace,
<       'k8s.node.name': df.destination_node,
---
>       'server.service.name': df.destination_service,
>       'server.k8s.pod.name': df.destination_pod,
>       'server.k8s.deployment.name': df.destination_deployment,
>       'server.k8s.namespace.name': df.destination_namespace,
>       'server.k8s.node.name': df.destination_node,
89,94c86,90
<           # NOTE: the integration handles splitting of services.
<           'parent.namespace.name': df.source_namespace,
<           'parent.service.name': df.source_service,
<           'parent.deployment.name': df.source_deployment,
<           'parent.node.name': df.source_node,
<           'parent.k8s.pod.name': df.source_pod,
---
>           'client.service.name': df.source_service,
>           'client.k8s.pod.name': df.source_pod,
>           'client.k8s.deployment.name': df.source_deployment,
>           'client.k8s.namespace.name': df.source_namespace,
>           'client.k8s.node.name': df.source_node,

Testing Done

• Created a custom export script for each of these in my cloud and verified they were successful