[config] Separate loading model with config from neuralnetwork class

[config] Separate loading model with config from neuralnetwork class

Loading the model from given ini file is separated from main neuralnetwork class
This will allow loading from other type of config files and keep neuralnetwork class cleaner

**Self evaluation:**
1. Build test: [x]Passed [ ]Failed [ ]Skipped
2. Run test: [x]Passed [ ]Failed [ ]Skipped

Signed-off-by: Parichay Kapoor <pk.kapoor@samsung.com>