feat: add support for `OTEL_SDK_DISABLED` environment variable

[iamsauravsharma]

Fixes #1936

Changes

Add support for OTEL_SDK_DISABLED environment variable using no-op SDK implementation as explained Opentelemetry SDK environment variable docs. When set to true, the SDK will provide no-op implementations for all API components (Tracer, Logger, and Meter).

Implemented no-op provider classes that mimic the shutdown no-op providers for logger and tracer with only difference is shutdown variable which is set to false for disabled no op. Where as for metrics existing noop is re used

Merge requirement checklist

• [X] CONTRIBUTING guidelines followed
• [X] Unit tests added/updated (if applicable)
• [X] Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• [ ] Changes in public API reviewed (if applicable)

[linux-foundation-easycla[bot]]

The committers listed above are authorized under a signed CLA.

• :white_check_mark: login: iamsauravsharma / name: Saurav Sharma (e2eb5fbf20fbc20f77be080d3af260a6f1d7ea0e)

[codecov[bot]]

Codecov Report

:x: Patch coverage is 28.03030% with 95 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 80.1%. Comparing base (2b63b75) to head (e2eb5fb).

Files with missing lines	Patch %	Lines
opentelemetry-sdk/src/logs/logger_provider.rs	18.7%	39 Missing :warning:
opentelemetry-sdk/src/trace/provider.rs	36.8%	36 Missing :warning:
opentelemetry-sdk/src/metrics/meter_provider.rs	29.1%	17 Missing :warning:
opentelemetry-sdk/src/logs/logger.rs	0.0%	3 Missing :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3088     +/-   ##
=======================================
- Coverage   80.5%   80.1%   -0.4%     
=======================================
  Files        129     129             
  Lines      23294   23420    +126     
=======================================
+ Hits       18756   18782     +26     
- Misses      4538    4638    +100     

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[iamsauravsharma]

Since overwriting OTEL_SDK_DISABLED environment variable would effects other test when running parallel test. 3 new test are ignored by default and scripts/test.sh is updated so 3 test run themselves in last step

[iamsauravsharma]

Implemented some changes as requested

[iamsauravsharma]

@cijothomas @lalitb just a reminder about this PR. I’ve pushed the requested changes or replied with my reasoning. could you please take another look?