Make Phortune payment methods transaction-oriented and always support "Add Payment Method"

Summary:
Depends on D20718. Ref T13366. Ref T13367.

• 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.

Test Plan:

• As a mechant-authority and account-authority, created payment methods from carts, subscriptions, and accounts. Edited and viewed payment methods.

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13367, T13366

Differential Revision: https://secure.phabricator.com/D20719