Make Phortune payment methods transaction-oriented and always support "Add Payment Method"
- Phortune payment methods currently do not use transactions; update them.
- Give them a proper view page with a transaction log.
- Add an "Add Payment Method" button which always works.
- Show which subscriptions a payment method is associated with.
- Get rid of the "Active" status indicator since we now treat "disabled" as "removed", to align with user expectation/intent.
- Swap out of some of the super weird div-form-button UI into the new "big, clickable" UI for choice dialogs among a small number of options on a single dimension.
- As a mechant-authority and account-authority, created payment methods from carts, subscriptions, and accounts. Edited and viewed payment methods.
Differential Revision: https://secure.phabricator.com/D20719