Map new telemetry distro attributes to agent fields for OTel distros

[estolfo]

The semantic conventions define two experimental attributes on a span.

• telemetry.distro.name
• telemetry.distro.version

These fields should be used to define the agent.Name and agent.Version fields.

The agent.Name should be, for example:

opentelemetry/java/elastic

and the agent.Version is the distro version.