ARROW-12671: [C++] Add OpenTelemetry to ThirdpartyToolchain

[lidavidm]

As discussed on the mailing list, this is a proof-of-concept that integrates OpenTelemetry for (distributed) tracing. This supports the following:

• OTel is used as a header-only library by default.
• Optionally, Arrow will link to OTel and configure it based on an environment variable.

No other instrumentation is added; this just sets up the build, and then we can consider what to instrument (FlightRPC, query engine, etc.) and also integrate more backends (Jaeger, OTLP, etc.).

[github-actions]

https://issues.apache.org/jira/browse/ARROW-12671

[lidavidm]

ML link for discussion: https://lists.apache.org/thread.html/re0db1b4d7a82f4cdb7bfab4bdd3620a9b3813a22626800d9772ccbda%40%3Cdev.arrow.apache.org%3E

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[ursabot]

Benchmark runs are scheduled for baseline = 200f167 and contender = bca0681. bca0681 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️1.61% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.44% ⬆️0.04%] ursa-thinkcentre-m75q
Supported benchmarks:
ursa-i9-9960x: langs = Python, R, JavaScript
ursa-thinkcentre-m75q: langs = C++, Java
ec2-t3-xlarge-us-east-2: cloud = True

[pitrou]

I'm curious: why are gRPC and protobuf required?

[lidavidm]

I'm curious: why are gRPC and protobuf required?

This PR configures the OTLP exporter so we can dump collected data somewhere where we can analyze it. The OTLP exporter talks to the OTLP collector over either HTTP or gRPC, using Protobuf payloads, so at least Protobuf and one of cURL and gRPC is required. We only enable the HTTP protocol, but the upstream CMake config currently doesn't differentiate between whether you have gRPC enabled or not when generating Protobuf stubs, so gRPC is unconditionally required. (See open-telemetry/opentelemetry-cpp#1045.) I think this may have just been fixed.

[pitrou]

It would be nice to make gRPC at least optional, as it's a rather heavy dependency.

[lidavidm]

The fix open-telemetry/opentelemetry-cpp@eca856d is in v1.1.0 so we should be able to remove the gRPC dependency in ARROW-14957.