Addition of Important Direction Gradient Integration (IDGI) framework

[ShreeSinghi]

🚀 Feature

Add a new attribution framework: IDGI, as described this paper in 2023

Motivation

The resulting saliency maps are much clearer and is not compute-heavy.

Pitch

IDGI is a framework that can be applied to any integrated gradients method (BlurIG, GIG etc.) however I propose implementing it for the vanilla integrated gradients method. The implementation of this would exist as a separate class and would not be dependant on the IntegratedGradients class

Additional context

https://arxiv.org/abs/2303.14242

I would like to work on the implementation of this framework