Replace EnvelopeGenerator.Service with Service_legacy

The project `EnvelopeGenerator.Service` has been removed from the solution and replaced with a new project, `EnvelopeGenerator.Service_legacy`.

Updated build configuration mappings to reflect the addition of `Service_legacy` and the removal of `Service`. Adjusted project nesting to place `Service_legacy` under the same parent as the removed `Service`.

EnvelopeGenerator.Service_legacy/ProjectInstaller.vb

@@ -0,0 +1,16 @@
+Imports System.ComponentModel
+Imports System.Configuration.Install
+
+Public Class ProjectInstaller
+
+    Public Sub New()
+        MyBase.New()
+
+        'Dieser Aufruf ist für den Komponenten-Designer erforderlich.
+        InitializeComponent()
+
+        'Initialisierungscode nach dem Aufruf von InitializeComponent hinzufügen
+
+    End Sub
+
+End Class