Optimizer to update gradients

Add an Optimizer system to complete Tensor update after gradient backpropagation.

changed milestone to %aidge_core - v0.2.0

added AddFeature Important IssueMissing Feature PriorityHigh StatusTODO labels

assigned to @pineapple and @thibaultallenet

added to epic &7 (closed)

created branch create_optimizer to address this issue

mentioned in merge request !82 (merged)

marked this issue as blocked by #80 (closed)

marked this issue as blocking #81 (closed)

changed health status to on track

These functionnality needs the Tensor::zeros() memeber function introduced in !89 (merged)

closed