Add Portal Settings Web Part with styles, localization, and tests

- Implemented the PortalSettings Web Part with a new manifest and TypeScript file.
- Created SCSS styles for the Web Part, defining various UI elements and responsive design.
- Added localization support for English and German languages.
- Developed tests for Provider Registry and static assets validation.
- Included PowerShell script for project validation.

config/config.json

@@ -2,17 +2,17 @@
   "$schema": "https://developer.microsoft.com/json-schemas/spfx-build/config.2.0.schema.json",
   "version": "2.0",
   "bundles": {
-    "portal-settings-application-customizer": {
+    "portal-settings-web-part": {
       "components": [
         {
-          "entrypoint": "./lib/extensions/portalSettings/PortalSettingsApplicationCustomizer.js",
-          "manifest": "./src/extensions/portalSettings/PortalSettingsApplicationCustomizer.manifest.json"
+          "entrypoint": "./lib/webparts/portalSettings/PortalSettingsWebPart.js",
+          "manifest": "./src/webparts/portalSettings/PortalSettingsWebPart.manifest.json"
         }
       ]
     }
   },
   "externals": {},
   "localizedResources": {
-    "PortalSettingsApplicationCustomizerStrings": "lib/extensions/portalSettings/loc/{locale}.js"
+    "PortalSettingsWebPartStrings": "lib/webparts/portalSettings/loc/{locale}.js"
   }
 }