OpenTelemetry Profiles signal

[jmacd]

Pre-filing checklist

• I searched existing issues and didn't find a duplicate

Component(s)

Rust OTAP dataflow (rust/otap-dataflow/), Go OTel Arrow Receiver/Exporter (go/)

Is your feature request related to a problem?

OpenTelemetry is adding the Profiles signal type. OTel-Arrow should add profiles.

Proposed Solution

As OTLP and Collector gain profiles support, we should add OTAP profiles support. Note that the profiles signal includes a new dictionary form of key-value making it relatively advanced for OTLP. We will be able to directly construct OTAP efficiently, but we need a signal definition for OTAP. See #1957

Alternatives Considered

No response

Additional Context

No response