mv_machine_learning: code refactoring to Inference class

mv_machine_learning: code refactoring to Inference class

[Issue type] : code refactoring

Did code refactoring to Run member function of Inference class by doing,
	- extracted a function which converts mv sources to cv ones. And
	  this converting function is now considered for multiple sources.
	- introduced a new util file which can contain common things
	  to be used by machine learning relevant code.
	- and did code sliding and renaming several variables.

This is just a step for next code refactoring and there are many things to do.

Change-Id: Ic78ef26156481def5ecda537657638c613a304d1
Signed-off-by: Inki Dae <inki.dae@samsung.com>