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/invoice/mutations.gql

@@ -10,6 +10,7 @@ mutation createInvoice(
   $invoiceNumber: String!
   $issueDate: Timestamp!
   $dueDate: Timestamp!
+  $hub: String
   $managerName: String
   $vendorNumber: String
   $roles: Any
@@ -35,6 +36,7 @@ mutation createInvoice(
       invoiceNumber: $invoiceNumber
       issueDate: $issueDate
       dueDate: $dueDate
+      hub: $hub
       managerName: $managerName
       vendorNumber: $vendorNumber
       roles: $roles
@@ -64,6 +66,7 @@ mutation updateInvoice(
   $invoiceNumber: String
   $issueDate: Timestamp
   $dueDate: Timestamp
+  $hub: String
   $managerName: String
   $vendorNumber: String
   $roles: Any
@@ -94,6 +97,7 @@ mutation updateInvoice(
       invoiceNumber: $invoiceNumber
       issueDate: $issueDate
       dueDate: $dueDate
+      hub: $hub
       managerName: $managerName
       vendorNumber: $vendorNumber
       roles: $roles