Split payment/verification business intelligence analytics

Track verify now and verify later choices from the payment confirmation page, image captures, image retake, and name changes, as well as virtual pageviews for every step in the new flow(s). For some pages in the flow, this will cause duplicate pageviews to appear in GA. However, marketing is aware of this and is okay with a slight skew in the pageview totals; they care more about being able to easily reconstruct a funnel which accurately represents the payment and verification flows.

@AlasdairSwan and @wedaly, could you review this when you're able?
Calls to `pageview` are contained within the old verification flow. However, since we often have Segment disabled while developing and the open source community might not be running it, it's possible that we'd see a runtime JS error breaking pages in the old verification flow. I'll add back the `pageview` attribute.