Update Docusaurus from .15 to .18 and update Python docs

app/docs/guides/training/python/01_introduction.md

app/docs/guides/training/python/02_interpreter.md

app/docs/guides/training/python/03_types.md

app/docs/guides/training/python/04_language_and_control.md

app/docs/guides/training/python/05_data_structures.md

app/docs/guides/training/python/06_modules.md

app/docs/guides/training/python/07_scope_class.md

app/docs/guides/training/python/08_error.md

app/docs/guides/training/python/09_virtual_env.md

app/docs/guides/training/python/injektalas.png

app/docs/guides/training/python/laszlo_rafael_min.jpg

app/package.json

app/sidebars.js

app/yarn.lock