colab version of the notebooks

[wzhang1]

Why you need this feature:
[Is your feature request related to a problem? Please describe in details]
google colab is an no setup needed jupyter notebook like tool, quite popular
for demo object detection, machine learning projects.

Describe the solution you'd like:
[A clear and concise description of what you want to happen.]

convert some notebook in this repo, for example "GroceriesReal_Analysis.ipynb",
to colab version, so that it's easy to try different models, hyper parameter, validation samples, or allow
user to infer on their own images
Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]
pls remove this if this is already in plan