[CI] New dedicated MacOS Integration pipieline

[pazone]

What does this PR do?

Creates a dedicated pipeline that will run MacOS integration tests called elastic-agent-macos-integration
This pipeline is currently not triggered by any github events.
Also adds the Scheduler pipeline that will later trigger elastic-agent-macos-integration pipeline for main and release branches every Tuesday.

Why is it important?

We need to run macOS tests in 2 cases:

• When a macos label is added to a PR (Will be implemented later)
• By a cron for the main and release branches

To accomplish this, we need a dedicated pipeline entity. The schedule and branch configuration will be added later.

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?
• ...

[v1v]

LGTM. Thanks for walking me through the specifics