send errors/warnings/etc by default through PHP's error_log. This gives more control to administrators, since error_log can
be configured to write to any stream (file, stderr, etc). I think it's also less surprising for people trying out otel (particularly
with development PHP settings, where trigger_error often breaks an application).
Adding a configuration value to control where logs go: OTEL_PHP_LOG_DESTINATION.
Brett McBride