wip: implement invoice generator for teamers

config/packages/flagception.yaml

@@ -10,3 +10,6 @@ flagception:
         datev_email:
             default: false
             env: FEATURE_DATEV_EMAIL
+        invoice_editor:
+            default: false
+            env: FEATURE_INVOICE_EDITOR

config/services.yaml

@@ -194,3 +194,7 @@ services:
             $defaults:
                 from: '%default_email_from%'
                 to: '%default_email_to%'
+
+    App\Service\Invoice\InvoicePdfGeneratorInterface: '@App\Service\Invoice\InvoicePdfGenerator'
+    App\Service\Invoice\InvoiceUploadWriterInterface: '@App\Service\Invoice\InvoiceUploadWriter'
+    App\Service\Invoice\InvoiceSubmissionServiceInterface: '@App\Service\Invoice\InvoiceSubmissionService'