Update NavMenu links and add commented-out navigation

- Added a commented-out block for "Home" and "Document Viewer (JS-Based)" navigation links.
- Updated the "reportviewer" link text to "Empfänger-UI."
- Updated the "reportdesigner" link text to "Umschlag-UI."

EnvelopeGenerator.ReceiverUI/Shared/NavMenu.razor

@@ -9,6 +9,7 @@
 
 <div class="@NavMenuCssClass" @onclick="ToggleNavMenu">
     <nav class="flex-column">
+        @*
         <div class="nav-item px-3">
             <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
                 <span class="oi oi-home" aria-hidden="true"></span> Home
@@ -19,14 +20,15 @@
                 <span class="oi oi-plus" aria-hidden="true"></span> Document Viewer (JS-Based)
             </NavLink>
         </div>
+        *@
         <div class="nav-item px-3">
             <NavLink class="nav-link" href="reportviewer">
-                <span class="oi oi-plus" aria-hidden="true"></span> Report Viewer (Native)
+                <span class="oi oi-plus" aria-hidden="true"></span> Empfänger-UI
             </NavLink>
         </div>
         <div class="nav-item px-3">
             <NavLink class="nav-link" href="reportdesigner">
-                <span class="oi oi-plus" aria-hidden="true"></span> Report Designer
+                <span class="oi oi-plus" aria-hidden="true"></span> Umschlag-UI
             </NavLink>
         </div>
     </nav>