feat: release pip

Context

#67 (closed)

This MR contains all changes required for the packaging of the aidge meta project.

This MR also intends to improve the overall installation process of the aidge pkg.

Changes

Build :

• Submodules
  • Added export_arm_cortexm as submodule
  • submodules have now a relative path rather than an http url
• setup.sh
  • better helpstring
  • now python pkg can be built in debug mode
• setup.py has been replaced with a pyproject.toml
• Upd readme with up to date installations instructions

CI

• Added build:ubuntu:python:pip job that builds aidge from online pkg. This job is triggered on :
  • scheduled jobs
  • tag creation
  • MR on main (failure allowed)
  • when pyproject.toml is changed
• Added release & deploy stages

Feature : generate_changelog.sh script

Very useful to... well generate changelogs. Maybe not up to date but really practical.