DB IO clean up work

Move methods around so they are grouped more logically. This is for a
future split out for function groups into sub classes to the main DB IO
class (private classes).

Also add a global variable $DB_CONFIG because setting this as constant
prevents us from override the debug config.
But for this add a third parameter to set debug flag override

www/configs/config.master.php

@@ -246,6 +246,8 @@ if (
 // define the db config set name, the db config and the db schema
 define('DB_CONFIG_NAME', $SITE_CONFIG[HOST_NAME]['db_host']);
 define('DB_CONFIG', isset($DB_CONFIG[DB_CONFIG_NAME]) ? $DB_CONFIG[DB_CONFIG_NAME] : []);
+// because we can't change constant, but we want to for db debug flag
+$GLOBALS['DB_CONIFG'] = DB_CONFIG;
 // define('DB_CONFIG_TARGET', SITE_CONFIG[$HOST_NAME]['db_host_target']);
 // define('DB_CONFIG_OTHER', SITE_CONFIG[$HOST_NAME]['db_host_other']);
 // override for login and global schemas