Move onboarding to the web #34366
Description
This removes a decent chunk of work from #33301, and it's something we've been planning to do anyway. Terms + training will be replaced with a one page "welcome" and link to the web onboarding.
We have good figma designs for this when you're ready to pick this up @incognitojam
There's a start at it here: https://github.com/commaai/web4/pull/112