feat(labels): implement label update functionality and enhance UI

- Added `updateLabel` method in `LabelsController` to handle label updates with validation for name and color.
- Updated API routes to include the new label update endpoint.
- Introduced `LabelsDrawer` component for editing labels, including a color picker and form validation.
- Enhanced localization files to support new UI strings for label management.
- Implemented a new `LabelsSettings` page to manage labels with search and edit capabilities.
- Improved color handling with a comprehensive color palette for better user experience.

worklenz-frontend/public/locales/de/settings/labels.json

@@ -7,5 +7,9 @@
   "searchPlaceholder": "Nach Name suchen",
   "emptyText": "Labels können beim Aktualisieren oder Erstellen von Aufgaben erstellt werden.",
   "pinTooltip": "Zum Anheften an das Hauptmenü klicken",
-  "colorChangeTooltip": "Zum Ändern der Farbe klicken"
+  "colorChangeTooltip": "Zum Ändern der Farbe klicken",
+  "pageTitle": "Labels verwalten",
+  "deleteConfirmTitle": "Sind Sie sicher, dass Sie dies löschen möchten?",
+  "deleteButton": "Löschen",
+  "cancelButton": "Abbrechen"
 }