Changed the orientation settings in PwaManifestBuilder.php from 'portrait' to 'any'. This allows the PWA to adjust to any screen orientation, enhancing user flexibility.
- Updated to go through HomeController with the builder as a helper
class.
- Extracted some reapeated items into variables in manifest.
- Updated background color to match those used by BookStack.
- Removed reference of icon.ico since its not intended to be used.
- Added tests to cover functionality.
Review of #4430
