Deprecate Zipkin exporter

[michaeljohnalbers]

Deprecates the Zipkin exporter and removes all dependencies on internal classes. This involved copying several classes into a sub-package of the Zipkin exporter package. There is a README.md in this package with a short explanation. Several test classes had to be updated to handle the deprecation.

First part of implementing #7863

[linux-foundation-easycla]

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• ✅ login: michaeljohnalbers / name: Michael Albers (5d21c39, 945379a, a14c2c9, ba8c91c, d91e565)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.16%. Comparing base (d6ad3ae) to head (5d21c39).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #7974   +/-   ##
=========================================
  Coverage     90.16%   90.16%           
  Complexity     7478     7478           
=========================================
  Files           836      836           
  Lines         22550    22550           
  Branches       2224     2224           
=========================================
  Hits          20333    20333           
  Misses         1515     1515           
  Partials        702      702           

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[jack-berg]

I think we should just mark the zipkin exporter as deprecated for now and come back to the problem of removing shared internal code later.

There are a couple of things we could do with the shared internal code which don't involve copying into the zipkin exporter:

• Promote those classes to our public API
• Carve out a new category of packages, maybe called *.tools.* or *.utils.*, which we guarantee from an API compatibility standpoint, but advertise as "not for public consumption". Move the shared internal code to this new category of packages.

[michaeljohnalbers]

@jack-berg I've updated the PR to remove copying to internal code.

[jkwatson]

Thanks!

[jack-berg]

Thanks!

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