feat(?): ⭐ New onboarding flow #126

[1] Feature Description
Our DB currently has a lot of unmigrated users in it, because we are storing their old connected teams. This spams both the build team user list and the general user list.

Ideally we would remove them as actual users and move them to either a seperate table or off of the DB entirely and migrate on demand.

This would open the option for a new "onboarding"/signup flow:

1. On buildtheearth.net click "Get Started"
2. Redirect to my.buildtheearth.net -> auth.buildtheearth.net signup
3. General KC signup flow (username)
4. If not linked to Discord, ask to link discord
5. "Done" page with links