Slice and Identity nodes for Tiling

What commit version of aidge do you use

• aidge_core: d79c4eb34e327e0b235e6194605d3039bac3b186
• aidge_export_cpp: 6fcda722

Description

Cf issue aidge_core#280 (closed) for the tiling feature, we need identity and slice nodes in order to seamlessly export a tiled model.

I think the identity node is needed though beeing trivial : the graph begins directly with the parallel sliced branches so the input needs to be affected to a single starting node. This way, the identity starting node is needed as input node for the next paralel slice nodes.

I'll try to implement those nodes in a future MR, don't hesitate to tell me if you have a better or more simple solution for the Identity node export.