[CONFIGURATION] File configuration - otlp exporter builders

[marcalff]

Contributes to #2481

This is a partial fix, to implement otlp exporter builders.

Changes

Please provide a brief description of the changes here.

• Add a new option constructor, that ignores environment variables
• Implement the otlp exporter builders

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[netlify]

✅ Deploy Preview for opentelemetry-cpp-api-docs canceled.

Name	Link
🔨 Latest commit	13295b8
🔍 Latest deploy log	https://app.netlify.com/projects/opentelemetry-cpp-api-docs/deploys/688725b1933cfc0008282df2

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.03%. Comparing base (2fc2a20) to head (13295b8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3566   +/-   ##
=======================================
  Coverage   90.03%   90.03%           
=======================================
  Files         220      220           
  Lines        7069     7069           
=======================================
  Hits         6364     6364           
  Misses        705      705           

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[dbarker]

Looks good. Thanks!