(core) Customizable stripe plans.

Summary:
- Reading plans from Stripe, and allowing Stripe to define custom plans.
- Storing product features (aka limits) in Stripe, that override those in db.
- Adding hierarchical data in Stripe. All features are defined at Product level but can be overwritten on Price levels.
- New options for Support user to
-- Override product for team site (if he is added as a billing manager)
-- Override subscription and customer id for a team site
-- Attach an "offer", an custom plan configured in stripe that a team site can use
-- Enabling wire transfer for subscription by allowing subscription to be created without a payment method (which is customizable)

Test Plan: Updated and new.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D4201

test/server/lib/DocApi.ts

@@ -5,7 +5,6 @@ import {SHARE_KEY_PREFIX} from 'app/common/gristUrls';
 import {arrayRepeat} from 'app/common/gutil';
 import {WebhookSummary} from 'app/common/Triggers';
 import {DocAPI, DocState, UserAPIImpl} from 'app/common/UserAPI';
-import {testDailyApiLimitFeatures} from 'app/gen-server/entity/Product';
 import {AddOrUpdateRecord, Record as ApiRecord, ColumnsPut, RecordWithStringId} from 'app/plugin/DocApiTypes';
 import {CellValue, GristObjCode} from 'app/plugin/GristData';
 import {
@@ -41,6 +40,7 @@ import {waitForIt} from 'test/server/wait';
 import defaultsDeep = require('lodash/defaultsDeep');
 import pick = require('lodash/pick');
 import { getDatabase } from 'test/testUtils';
+import {testDailyApiLimitFeatures} from 'test/gen-server/seed';
 
 const chimpy = configForUser('Chimpy');
 const kiwi = configForUser('Kiwi');