Image Normalization Mapper - Batch Mode

Proposed Features

Add a mapper which can do image normalization and be passed to dataset.map
Mapper should work in batch mode, just like rest of our mappers in https://github.com/faizanahemad/FastNet/blob/master/fastnet/data/image_augmentations.py
Put the function in https://github.com/faizanahemad/FastNet/blob/master/fastnet/data/image_augmentations.py

How the API looks like?

def get_image_normalizer(mean,std):
    """
    mean,std is the mean,std of 3 channels individually like [100, 81.1, 92],[12.1, 13.2, 21.5]
    """
    def transformer(x):
        ## your code here should normalize the images coming in x-tensor
        ## x is of shape [batch_size,Height,Width,Channels]
    return transformer

Intended Usage Like how mappers are used here and here

Limitations

Online References/Documentation was referred while making this API

Branch Name (The github branch in which you are working on this).

Note: Before raising a PR make sure that you have made an issue like this with tag: enhancement, ensure your code is tested and documented.

faizanahemad / FastNet

Image Normalization Mapper - Batch Mode #4