refactor(settings): polish database tab section structure

Drop the redundant inner Advanced TreeNode in the Maintenance section,
flatten the duplicated indent in the Overview section, and rename the
section headings so they reflect their content (Overview shows
metadata, Maintenance hosts the shift-gated tooling).

ChatTwo/Resources/HellionStrings.de.resx

@@ -528,9 +528,9 @@
     <value>Speicherung</value>
   </data>
   <data name="Settings_Database_Viewer_Heading" xml:space="preserve">
-    <value>DB-Viewer</value>
+    <value>Übersicht</value>
   </data>
   <data name="Settings_Database_Stats_Heading" xml:space="preserve">
-    <value>Statistiken</value>
+    <value>Wartung</value>
   </data>
 </root>

ChatTwo/Resources/HellionStrings.resx

@@ -528,9 +528,9 @@
     <value>Storage</value>
   </data>
   <data name="Settings_Database_Viewer_Heading" xml:space="preserve">
-    <value>DB Viewer</value>
+    <value>Overview</value>
   </data>
   <data name="Settings_Database_Stats_Heading" xml:space="preserve">
-    <value>Statistics</value>
+    <value>Maintenance</value>
   </data>
 </root>