Implement Stepper component

[replygirl]

Implement the new Stepper component design, used as the timeline for Tour pages.

interface StepperProps {
  lastStepNextLabel?: string // label for next button on final step. if undefined, fall back to 'Next'
  onFirstStepPreviousClick?: Function // event handler for previous button on first step. if undefined, fall back to onPreviousTap
  onNextClick?: Function // event handler for next button. if undefined, disable button
  onPreviousClick?: Function // event handler for previous button. if undefined, disable button
  onLastStepNextClick?: Function // event handler for next button on final step. if undefined, fall back to onNextTap
}

Dependencies

• Implement Button component #67

Design assets

• Component
• On-page (mobile)
• On-page (tablet+desktop)

[replygirl]

Blocked until #67 is closed