[Setup] Add support for editable mode

Context

Add support for editable/development mode build.

Basically reported necessary changes for supporting build in development mode with:

Refer to same changes done in aidge_core merge request aidge_core!154 (merged)

Modified files

Modified:

• setup.py: account for editable mode and pass python module installation directory to cmake, remove useless copy of module now directly installed by cmake
• cmake: add installation of python module
• README.md: add short description and refer to aidge_core README for details

Detailed major modifications

No incompatible modification. Add new support for development mode.

TODO

Nope