UI for YPP authorization flow

**Scope:**

- [ ] Implement all the UI and forms used in YPP authorization flow - https://www.figma.com/file/oQqFqdAiPu16eeE2aA5AD5/YouTube-Partner-Program?node-id=1774%3A115618

**OOP:**

- [ ] Google authentication
- [ ] YPP backend
- [ ] YouTube criteria validation