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-front/src/modules/databases/graphql/fragments/databaseConnectionFragment.ts

@@ -8,7 +8,7 @@ export const DATABASE_CONNECTION_FRAGMENT = gql`
     foreignDataWrapperOptions
     foreignDataWrapperType
     userMappingOptions {
-      username
+      user
     }
     updatedAt
     schema