feat: Strip setuptools

[astuyve]

What does this PR do?

setuptools contains binaries for every major architecture, but it's already included in the lambda runtime, so we don't need it.

I found this by pulling the python base images and running an interpreter, finding that setuptools is resolved just fine:

✗ docker run -it --entrypoint sh  public.ecr.aws/lambda/python:3.10
sh-4.2# python
Python 3.10.9 (main, Mar 31 2023, 16:38:53) [GCC 7.3.1 20180712 (Red Hat 7.3.1-15)] on linux
Type "help", "copyright", "credits" or "license" for more information.

>>>import os.path
>>>import setuptools

>>> print(os.path.abspath(setuptools.__file__))
/var/lang/lib/python3.10/site-packages/setuptools/__init__.py
>>>

TODO - need to verify that the provided version doesn't conflict with our own, need to verify that dd-trace-py source code integration still works with this stripped. But integration tests pass and that's a very good sign.

Should save us 3mb.

Motivation

Testing Guidelines

Additional Notes

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)

[duncanista]

LGTM

[joeyzhao2018]

Integration tests done:

• Published the layers to sandbox us-east-1 version3 and used by self-monitoring apps for 12 hours +
• Also use those layers and ran test lambda functions for following code:

    from ddtrace.vendor.psutil import _psutil_linux
    print(dir(_psutil_linux))
    from ddtrace.vendor.wrapt import _wrappers
    print(dir(_wrappers))
    import ddtrace.sourcecode.setuptools_auto
    import setuptools
    print(setuptools.__spec__) # this will have origin='/var/lang/lib/python3.<X>/site-packages/setuptools/__init__.py'
    print(setuptools.find_packages(where='mypkg', include=['pkg*'],))

this proves that 1. already installed extension modules in ddtrace still work even we removed the setuptools that we used to install ddtrace. 2. when user importing setuptools, it's using the runtime's setuptools anyway.

Based on those testings, this PR is safe to merge