Add log handler configuration to autoinstrumentation

[JWinermaSplunk]

Description

Add support for OTEL_PYTHON_LOG_HANDLER_LEVEL environment variable to configure log handler level in auto instrumentation.

Fixes open-telemetry/opentelemetry-python#4034

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Added test cases in test_handler.py and test_logging.py

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[pmcollins]

Looking good, thanks for the change. Added a few minor comments.

[MikeGoldsmith]

🚀

[pmcollins]

LGTM, thanks. Added a doc suggestion.

[pmcollins]

Nit: could add more explanation about what it means to set the log level of the logging handler. e.g.

Set this env var to filter which log records are exported by OpenTelemetry. Only records at or above this level will be exported. For example, setting this to warning means DEBUG and INFO logs are still handled by your normal logging setup but are not exported as OTel logs.