chore: add lab for depth first search in frontend cert (JS only)

[jdwilkin4]

There will be lectures videos to talk about different graphs. But we need a lab for them to do it themselves.

In the coding interview prep section, we already have this interactive challenge https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/depth-first-search

Convert that challenge, into the lab format.

Acceptance criteria

• [ ] create a new folder of the project in the frontend-cert/js-projects directory
• [ ] add your completed project in an script.js file in that new folder
• [ ] create a markdown file for your proposed user stories. You should call it user-stories.md and place it in your new project folder