Reorganize onboarding concerns into a central class

Problem to solve

Currently the onboarding logic is strewn across helpers, controllers, views, etc and is hard to maintain and reason about. This also lends to it being very rigid to change/fragile.

Solution

Use the facade pattern to create a more centralized and maintainable code around onboarding.

This will also allow for seamless changing in logic away from params to a database/redis solution if desired. In essence a sort of adapter pattern here to insulate us from typical shotgun surgery that can be the case today if changes are made.