Load data infile invoke cpimport (if configured)

cpimport runs with default values ,
which in some cases not optimal.

Example:

if read buffer is not sufficient, LDI can fail with

terminate called after throwing an instance of 'std::runtime_error'

  what():  Data Row too BIG to handle!!

Which can loaded with increasing read buffer
cpimport -c <higer value>

This is not possible with LDI,
so a config file like cpimport_ldi.cnf

where the default values can be changed for cpimport would be a possible solution.