Fix console debug logs for otlp exporters.

[marcalff]

Fixes #1847

Changes

Fixed console debug logs for otlp exporters.

• Removed DEBUG: text from logs, redundant with OTEL_INTERNAL_LOG_DEBUG
• Fixed a broken OTLP HTTP Client] tag
• Added a space after FILE:LINE to separate from the log message
• Added usage comments in examples
• Set GlobalLogHandler::SetLogLevel(LogLevel::Debug) in examples when console_log is enabled

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

[codecov]

Codecov Report

Merging #1848 (9e1c450) into main (57bf8c2) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1848   +/-   ##
=======================================
  Coverage   85.73%   85.73%           
=======================================
  Files         171      171           
  Lines        5240     5240           
=======================================
  Hits         4492     4492           
  Misses        748      748           

Impacted Files	Coverage Δ
sdk/src/common/global_log_handler.cc	87.50% <100.00%> (ø)

[owent]

LGTM

[lalitb]

Thanks.

[esigo]

LGTM
Thanks for the fix :)