Improve trace config startup logic

[bobbingwide]

oik-bwtrace v2.x used to support a constant named BW_TRACE_CONFIG_STARTUP.
Its purpose was to enable tracing as soon as the wp-config.php file was loaded.

Requirement

Enable tracing from the loading of the wp-config.php file

define( 'BW_TRACE_CONFIG_STARTUP', true );
if ( file_exists( ABSPATH . '/wp-content/plugins/oik-bwtrace/libs/bwtrace.php' ) ) { 
  require_once( ABSPATH . '/wp-content/plugins/oik-bwtrace/libs/bwtrace.php' );
}  

Proposed solution

• Check the current status of the logic.
• Add support for exporting the current trace options and action options configuration to a flat file ( JSON? ) so that they can be loaded when the database is not available.
• We have to find a way to hide the trace files directory... perhaps this should be what needs to be put in BW_TRACE_CONFIG_STARTUP.
• Document the new solution
• Check what logic's required in _oik_bwtrace_mu.php and db.php.