Roll Over Previous Year Volunteers as Interested Students

Issue Description

CELTS originally wanted interested students to roll over from the previous year while also adding an expiration period for that interest. Instead of carrying over all interested students and managing an expiration date, we decided to roll over only students who actually volunteered during the previous year.

These students should automatically be treated as interested students for the new year.

Expected Behavior
Students who volunteered during the previous year are automatically carried over as interested students for the new year.
Students who were only marked as interested but did not volunteer are not carried over.
No separate expiration system is needed for interested students.