[Feat] Add aidge_cmp and dev_mode directly into ExportNode

Context

• aidge_cmp is used to compare the feature maps of an exported model with aidge_backend_cpu results at inference time.
• dev_mode is used to generate symlinks of exported files instead of copies to ease the development process.
  Both are attributes of the ExportNodeCpp.

Features

• aidge_cmp and dev_mode used to be set as attributes of the export node within each operator. It is now directly set in the ExportNodeCpp itself.