Add NewBeatReceiver function for beats as otel receivers

[leehinman]

Proposed commit message

This PR adds a new function NewBeatReceiver to instantiate a beat as an otel receiver. The code is similar to the createBeater and configure functions. It is separate to so that understanding of tel receivers doesn't leak into to existing Beat setup. This also makes it much safer to change the receiver setup without breaking the traditional beat setup.

Checklist

• 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.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Disruptive User Impact

None

Author's Checklist

• [ ]

How to test this PR locally

Integration tests will catch if this change breaks regular beats instantiation. When receivers are added that will test that the new function works correctly.

Related issues

• Closes Refactor Beat instantiation and setup #40659

Use cases

Screenshots

Logs

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @leehinman? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-8./d is the label to automatically backport to the 8./d branch. /d is the digit

[mergify]

backport-8.x has been added to help with the transition to the new branch 8.x.
If you don't need it please use backport-skip label and remove the backport-8.x label.

[botelastic]

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[cmacknz]

I like this, thanks! I would like to make sure we have a test that creates a beat receiver with this method eventually, but I also recognize that requires a lot of work we haven't done yet.