Create a course planner walkthrough on the frontend

[jreinstra]

When an user creates an account and decides to make a course plan, they should get a beautiful and intuitive (or at least functional) interactive walkthrough that helps them get started. This should create the appropriate Plan and PlanQuarter APIs on the frontend. This should include asking the user their starting and ending years and their current major / minor preference (optional).

For now, let's just activate this when an user clicks on their "planner" tab for the first time - we can figure out a better registration flow later.