Make Cloud9 as a standard environment for the workshop

There are many unclear description that request the user to do a work depending on the environment. (like file download, or AWS CLI installation, python installation, etc.).

It can make the workshop to be disturbed by the diversity of the user environment.

Like other workshop, let's make Cloud9 as a standard workshop environment for simplicity and clearance.

The issue names no files or tests; start by locating the workshop instructions that cover file downloads, AWS CLI setup, and Python installation. Review those environment-dependent steps and update the documentation to use Cloud9 consistently, with the workshop instructions providing a single standard environment.

Written by the indexing model from the issue text.