Add MDquiz questions assessing overarching understanding of functions throughout our materials

We currently have one questions about functions in teacher starting and ending benchmarks for Algebra, DS, and Algebra2. We intend to collect some comparable information from students.

<img width="756" alt="Image" src="https://github.com/user-attachments/assets/d7acfdcf-ca26-49c0-95a7-252fa92b2171" />