Add `tflite-runtime` to python packages

[czlucius]

Add Tensorflow Lite to Python 3 pip packages, to enable the running of AI/ML algorithms on Piston. Compared to the regular tensorflow, the lite version is much smaller (see https://pypi.org/project/tflite-runtime/#files) - the download size is just 2.5 MB and after downloading, it occupies just 6.84 MB on my computer, smaller than even NumPy (it requires numpy as a dependency though)

The required pip package would be tflite-runtime. https://www.tensorflow.org/lite/guide/python https://pypi.org/project/tflite-runtime

I will make a PR soon. Thanks!