function deletes an existing file or group of files. The argument file_name
is either a string expression giving a file name or is a file handler declared in a file
statement in PROC GLOBAL
You can use the wildcard characters "*" and "?" to specify a group of files to delete.
The function returns the number of files deleted. If there was an error deleting files, the function returns default
// delete all data from the backups folder
(Application) + "Backups/*.csdb"