Link dataconnect package and add invoice hub

Wire up the dataconnect-generated package for the web app and add a new `hub` field to invoice mutations and queries. Updates include: add package links in apps/web package and workspace config, adjust connector.yaml JavaScript SDK output/package paths, add `hub` to invoice create/update mutations and to invoice queries, remove many example dataconnect GraphQL files and the web README, and minor formatting/newline fixes (Makefile and several .gql files).

backend/dataconnect/connector/order/mutations.gql

@@ -97,4 +97,4 @@ mutation updateOrder(
 
 mutation deleteOrder($id: UUID!) @auth(level: USER) {
   order_delete(id: $id) 
-}
+}