New Code Example : Forward-Forward Algorithm for Image Classification (#1170)

* added ForwardForward py file example for PR review

Signed-off-by: Suvaditya Mukherjee <suvadityamuk@gmail.com>

* added changes as per Francois's comments

Signed-off-by: Suvaditya Mukherjee <suvadityamuk@gmail.com>

* Copyedits

* added small final edits and generated files

Signed-off-by: Suvaditya Mukherjee <suvadityamuk@gmail.com>

Signed-off-by: Suvaditya Mukherjee <suvadityamuk@gmail.com>
Co-authored-by: François Chollet <francois.chollet@gmail.com>

Author: suvadityamuk