[TASK] Improve the menues in section Administration (TYPO3-Documentation#4922)

* [TASK] Improve the menues in section Administration

releases: main, 13.4, 12.4

* [TASK] Improve menu structure in Administration chapter

releases: main, 13.4, 12.4

Author: linawolf

Documentation/Administration/Index.rst

@@ -34,5 +34,8 @@ TYPO3 administration
     :glob:
 
     Installation/Index
+    Upgrade/Index
+    UserManagement/Index
+    Troubleshooting/Index
     */Index
     *

Documentation/Administration/PermissionsManagement/Index.rst

@@ -1,11 +1,12 @@
+:navigation-title: Permissions
 .. include:: /Includes.rst.txt
 
 .. index:: backend, acl, permissions, user groups, user management
 
 .. _permissions-management:
 
 ======================
-Permissions Management
+Permissions management
 ======================
 
 .. warning::

Documentation/Administration/Upgrade/Index.rst

@@ -1,13 +1,11 @@
-.. include:: /Includes.rst.txt
+:navigation-title: Upgrades
+..  include:: /Includes.rst.txt
 
-.. _upgrading:
+..  _upgrading:
 
-===================
-TYPO3 Upgrade Guide
-===================
-
-This chapter explains how to upgrade TYPO3 and migrate from Legacy to Composer
-mode.
+=======================================
+Upgrading the TYPO3 Core and extensions
+=======================================
 
 ..  card-grid::
     :columns: 1
@@ -54,14 +52,14 @@ mode.
 
         This chapter details how pages and content can be exported and then imported into another installation of TYPO3.
 
-.. toctree::
-   :hidden:
-
-   Minor/Index
-   Major/Index
-   UpgradingExtensions/Index
-   Tools/Index
-   Legacy/Index
-   ApplyingCorePatches/Index
-   MigrateToComposer/Index
-   MigrateContent/Index
+..  toctree::
+    :hidden:
+
+    Minor/Index
+    Major/Index
+    UpgradingExtensions/Index
+    Tools/Index
+    Legacy/Index
+    ApplyingCorePatches/Index
+    MigrateToComposer/Index
+    MigrateContent/Index

Documentation/Administration/UserManagement/Index.rst

@@ -1,10 +1,11 @@
+:navigation-title: Backend users
 ..  include:: /Includes.rst.txt
 
 
 ..  _user-management:
 
 =======================
-Backend User Management
+Backend user management
 =======================
 
 ..  important::