Append the Script Directory to PYTHONPATH

[benoit-dubreuil]

Specifications

• For the generated Python virtual environment (#96), or somehow at the project's root directory level, append the conf/script/src directory to the PYTHONPATH environment variable.
• It must work for the generated build target directories (#128).

Tips

• See https://docs.python.org/3/library/sys.html#sys.path
• See https://docs.python.org/3/using/cmdline.html#envvar-PYTHONPATH
• See https://docs.python.org/3/library/site.html#module-site
• Generate a .pth script inside the venv directory (which is also sys.prefix when the venv is activated).
  • Write the single line ../src inside that .pth script.