Purchases: Edit Payment Method v1

[mikeshelton1503]

For Purchases v1 there are a couple issues that need to resolved with the Edit Payment Method. 10647-gh-calypso-pre-oss outlines all of the changes but for v1 we will only provide the ability to edit a card.

1. The highest priority issue is that the form isn't functional. It still has placeholder data in it.
2. Currently the Edit Payment Method screen looks like this:

The labels need top padding to separate them from the input above. Also the proposed design for this also matches (almost) the same form layout of checkout: