mv_machine_learning: introduce MachineLearningConfig class

mv_machine_learning: introduce MachineLearningConfig class

[Issue type] : new feature

Introduce MachineLearningConfig class which parses configuration
and meta files for each task group.

Until now, we have fixed the code smell, divergent change, of each task group
by extracting parsing portion from each concrete class of each task group,
and we conformed that the parsing portions can be used commonly for all
task groups.

This patch introduces a new common configuration class, MachineLearningConfig
by moving all parsing portions to this class. As a first use case,
this patch makes ObjectDetection3d task group to use the MachineLarningConfig
class instead of internal code, ObjectDetection3dConfig class so it drops
all relevant internal code - finally, we can drop the ugly code duplication.

Change-Id: I8f6a3c276e61903350fd1ae4390f7b125931b2b3
Signed-off-by: Inki Dae <inki.dae@samsung.com>