Adjust payment workflows to deal with merchants and configurable providers in Phortune

Summary:
Ref T2787. Builds on D10649 by rebining existing objects (carts, charges, etc) to merchantPHIDs and providerPHIDs instead of an implicit global merchant and weird global artifacts (providerType / providerKey).

Basically:

  - When you create something that users can pay for, you specify a merchant to control where the payment goes.
  - Accounts are install-wide, but payment methods are bound to merchants. This seems to do a reasonable job of balancing usability and technical concerns.
  - Replace a bunch of weird links between objects with standard PHIDs.
  - Improve "add payment method" flow.

Test Plan: Went through the Fund flow with Stripe and WePay, funding an initiative.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T2787

Differential Revision: https://secure.phabricator.com/D10652

resources/sql/autopatches/20141007.fundmerchant.sql

@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_fund.fund_initiative
+  ADD merchantPHID VARBINARY(64);

resources/sql/autopatches/20141007.phortunecartmerchant.sql

@@ -0,0 +1,5 @@
+ALTER TABLE {$NAMESPACE}_phortune.phortune_cart
+  ADD merchantPHID VARBINARY(64) NOT NULL;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_cart
+  ADD KEY `key_merchant` (merchantPHID);

resources/sql/autopatches/20141007.phortunecharge.sql

@@ -0,0 +1,16 @@
+TRUNCATE TABLE {$NAMESPACE}_phortune.phortune_charge;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_charge
+  DROP paymentProviderKey;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_charge
+  ADD merchantPHID VARBINARY(64) NOT NULL;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_charge
+  ADD providerPHID VARBINARY(64) NOT NULL;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_charge
+  ADD KEY `key_merchant` (merchantPHID);
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_charge
+  ADD KEY `key_provider` (providerPHID);

resources/sql/autopatches/20141007.phortunepayment.sql

@@ -0,0 +1,16 @@
+TRUNCATE TABLE {$NAMESPACE}_phortune.phortune_paymentmethod;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_paymentmethod
+  DROP providerType;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_paymentmethod
+  DROP providerDomain;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_paymentmethod
+  ADD merchantPHID VARBINARY(64) NOT NULL;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_paymentmethod
+  ADD providerPHID VARBINARY(64) NOT NULL;
+
+ALTER TABLE {$NAMESPACE}_phortune.phortune_paymentmethod
+  ADD KEY `key_merchant` (merchantPHID, accountPHID);