[Package] emio Python package

[EulalieCoevoet]

Implements #33

In this PR:

1. Moves parts/ , utils/ folders and parameters.py file in the new folder emio/
2. Package emio. New usage:
   • from emio import Emio, EmioGUI
   • import emio.parameters as parameters

TODO:

• Add deprecation management
• Update external labs and demos:
  • Emio.lab_empty
• Update documentation:
  • Migration
  • Docs

[HanaeRateau]

With the deprecation implemented in 89a88cf and 9fa1260, we don't need to wait for updating the other labs except for lab_empty i think.