[Woo POS] Totals view

[iamgabrielma]

After tapping in checkout, we'll have a "Totals" view with some sort of accumulated data and the payment buttons:

[dangermattic]

Thanks for reporting! 👍

[iamgabrielma]

Keeping this open since the linked PRs are only to render the view and show some data, but nothing final yet.