Add stack lab to main

[jdwilkin4]

We have this stack challenge in the interview prep section.

https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/create-a-stack-class

This would work well as a lab in the new DSA modules in the JS cert.

This original challenge works with JS classes. But the majority of the cert mainly deals with regular functions. So it would be better to convert this challenge to just use regular functions instead of classes.

Here is where this lab will go in the curriculum order

NOTE: this is blocked until the PR to add the DSA modules has been merged into main.