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/config.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/spfx-build/config.2.0.schema.json",
+  "version": "2.0",
+  "bundles": {
+    "accordion-web-part": {
+      "components": [{
+        "entrypoint": "./lib/webparts/accordion/AccordionWebPart.js",
+        "manifest": "./src/webparts/accordion/AccordionWebPart.manifest.json"
+      }]
+    }
+  },
+  "externals": {},
+  "localizedResources": {
+    "AccordionWebPartStrings": "lib/webparts/accordion/loc/{locale}.js"
+  }
+}
+