Add macrobenchmark runs

[ddyurchenko]

Description

Allow running PHP laravel-realworld macrobenchmark directly from repository on Gitlab.

This PR enables 2 ways to run macrobenchmark:

1. Automatically on every new commit in master branch.
2. Manually on any commit in any branch.

Limitations

Due to how releases are downloaded from CircleCI, allows running macrobenchmark only on any of the last 20 commits from the target branch.

How to run benchmark manually

In your corresponding Gitlab pipeline, do the next steps:

1. Run download_circle_ci_release job, so correct datadog-setup.php is downloaded from CircleCI.
2. Run any / all macrobenchmark variants jobs. You won't be able to trigger benchmark job till download_circle_ci_release is complete.

How to see the results

In your Gitlab job, you will see the link to Datadog UI dashboard to monitor progress continuously, and after benchmark run is finished, also a link to BP UI.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[PROFeNoM]

Thank you! 😃