Add Accordion web part implementation with dynamic SharePoint list integration

- Created Accordion web part with SPFx 1.4.1 framework.
- Implemented dynamic loading of SharePoint lists and fields.
- Added configuration options for title, content, and category fields.
- Included support for multiple open sections and initial state settings.
- Developed HTML sanitizer for rich text content.
- Implemented accessible accordion UI with category grouping.
- Added localization support for English and German languages.
- Created necessary configuration files for deployment and asset management.
- Added validation script to ensure project compliance with standards.

config/package-solution.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/spfx-build/package-solution.schema.json",
+  "solution": {
+    "name": "accordion-client-side-solution",
+    "title": "Accordion",
+    "id": "27a6fd90-42a1-4e39-8862-08ed0e7803bc",
+    "version": "1.0.0.0",
+    "includeClientSideAssets": true,
+    "skipFeatureDeployment": true
+  },
+  "paths": {
+    "zippedPackage": "solution/accordion.sppkg"
+  }
+}
+