Update to Angular v21

[lukasmatta]

This pull request updates the project to Angular 21 and Node.js 22, modernizes build tooling, and improves configuration for testing and markdown sanitization. The main focus is on dependency upgrades, workflow improvements, and compatibility updates.

Dependency and Compatibility Upgrades:

• Upgraded all Angular packages and related dependencies (including cps-ui-kit, ngx-markdown, and marked) to versions compatible with Angular 21 in both package.json and projects/cps-mdoc-viewer/package.json. [1] [2]
• Updated zone.js and other dev dependencies (e.g., jest, @angular-builders/jest, @angular-eslint/*) to latest compatible versions.

GitHub Actions Workflow Modernization:

• Updated all workflows to use actions/checkout@v5, actions/setup-node@v5, and Node.js v22.x; replaced manual cache steps with the built-in cache: 'npm' option. [1] [2] [3] [4]

Testing and Build Configuration:

• Added "zoneless": false to the Jest test builder options in angular.json to ensure compatibility with Angular 21's testing requirements. [1] [2]
• Updated example app bootstrap to use provideZoneChangeDetection() for compatibility with Angular 21's zone handling.

Markdown and Security Handling:

• Updated markdown provider configuration to use the new SANITIZE injection token in projects/cps-mdoc-viewer/src/lib/lib.provider.ts, reflecting changes in ngx-markdown v21. [1] [2]

Other Improvements:

• Added omit-lockfile-registry-resolved=true to .npmrc for improved lockfile handling.
• Cleaned up unused event parameter in @HostListener for scroll handling.

[TerranceKhumalo-absa]

maybe in the future we can use host instead of @HostListener as that's the recommended approach :)