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.

gulpfile.js

@@ -2,20 +2,4 @@
 
 const build = require('@microsoft/sp-build-web');
 
-build.addSuppression(`Warning - [sass] The local CSS class 'ms-Grid' is not camelCase and will not be type-safe.`);
-
-// Custom Task: Kopiere Feature- und Settings-Assets in den Output-Ordner
-const copyAssets = build.subTask('copy-settings-assets', function (gulp, buildOptions, done) {
-  return gulp.src([
-    'src/assets/*.aspx',
-    'src/assets/*.html',
-    'src/assets/*.css',
-    'src/assets/*.xml'
-  ])
-  .pipe(gulp.dest('sharepoint/assets'));
-});
-
-// Task vor dem Bundle ausfuehren
-build.rig.addPreBuildTask(copyAssets);
-
 build.initialize(require('gulp'));