Create tflkit directory (#3438)

Create tflkit directory (#3438)

* Create tflite_easytool directory

This directory is created to make it easier to run frequently used tools in scripts.
Now, it has two functions:
- Summraize PB model
- Summraize TfLite model

Signed-off-by: Jiyoung Yun <jy910.yun@samsung.com>
* Change the directory name to tflkit

Also changes the relative path to absolute path

Signed-off-by: Jiyoung Yun <jy910.yun@samsung.com>
* Add Prerequires and TF tool guideline

Signed-off-by: Jiyoung Yun <jy910.yun@samsung.com>
* Add additional description for prerequires

Signed-off-by: Jiyoung Yun <jy910.yun@samsung.com>