Add the tailsampling OpenTelemetry processor

[estolfo]

What does this PR do?

Add the tailsampling processor to EDOT.

Why is it important?

This is important so that users can use the tail sampling feature with EDOT, as it's a valued feature of the APM server and we'd like to provide a similar experience for users with EDOT.

Checklist

• I have read and understood the pull request guidelines of this project.
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

How to test this PR locally

Related issues

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

[mergify]

This pull request does not have a backport label. Could you fix it @estolfo? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-./d./d is the label that automatically backports to the 8./d branch. /d is the digit
• backport-active-all is the label that automatically backports to all active branches.
• backport-active-8 is the label that automatically backports to all active minor branches for the 8 major.
• backport-active-9 is the label that automatically backports to all active minor branches for the 9 major.

[estolfo]

Resolves https://github.com/elastic/opentelemetry-dev/issues/1041

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: fb8ce12

History

• 💔 Build #25865 failed fb8ce12
• 💔 Build #25861 failed 61b5b50
• 💔 Build #25850 failed 7ea268e

cc @estolfo

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[swiatekm]

@estolfo does this need to be backported into previous minor releases?

[estolfo]

@sboomsma do you know if we need to backport this?