Build stripe integration on backend side (#5246)

Adding stripe integration by making the server logic independent of the
input fields:
- query factories (remote server, foreign data wrapper, foreign table)
to loop on fields and values without hardcoding the names of the fields
- adding stripe input and type
- add the logic to handle static schema. Simply creating a big object to
store into the server

Additional work:
- rename username field to user. This is the input intended for postgres
user mapping and we now need a matching by name

---------

Co-authored-by: Thomas Trompette <thomast@twenty.com>

packages/twenty-server/src/database/typeorm-seeds/core/feature-flags.ts

@@ -45,6 +45,11 @@ export const seedFeatureFlags = async (
         workspaceId: workspaceId,
         value: true,
       },
+      {
+        key: FeatureFlagKeys.IsStripeIntegrationEnabled,
+        workspaceId: workspaceId,
+        value: true,
+      },
     ])
     .execute();
 };