Added video processing section (Unit 7 - Transformers based models)

[mreraser]

Co-authored-by: seoulsky-field [email protected]

What does this PR do?

Added Transformers based models at video processing section. This document provides an overview of how Transformer models are applied in video processing, focusing on the Vision Transformer (ViT) and its video-specific variant, the Video Vision Transformer (ViViT), and TimeSFormer model.

Thank you in advance for your review.

Part of Proposed Outline Revision for Unit 7. Video & Video Processing / dicussions #348

Who can review?

@jungnerd @cjfghk5697 @1kmmk1 and anyone who wants to review!

Who can review (Final)