[#12048] data migration student chain students

[mingyuanc]

Part of #12048

Outline of Solution

• Cascade migrate course, sections, teams and student
• Verify migrated course, sections, teams and student
• Change createdAt to be updatable(Remove creationTimeStamp annotation from createdAt)
• Remove updateTimeStamp annotation from updatedAt

Things left to do in other PR

• [ ] Follow up from fergus on usage of DEFAULT_SECTION or DEFAULT_SQL_SECTION
• [ ] Shutdown hook or its equivalent
• [ ] migrateFeedbackChain method
• [ ] verifyCourseEnitity Method or its equivalent

[github-actions[bot]]

Hi @mingyuanc, thank you for your interest in contributing to TEAMMATES! However, your PR does not appear to follow our contribution guidelines:

• Description must reference the issue number the PR is fixing, e.g. Fixes #<issue-number> (or Part of #<issue-number> if the PR does not address the issue fully)

Please address the above before we proceed to review your PR.