New feature and documentation update

[BoiHanny]

PR Classification

New feature and documentation update.

PR Summary

This PR introduces a new feature for .NET 8 installation and updates the README for better clarity and additional information.

• README.md: Updated with new images, download links, and additional sections for features, dependencies, and contact.
• App.xaml.cs: Added -installDotNetAdmin argument and InstallDotNet method for .NET installation.
• UpdateApp.cs: Added InstallDotNet method and DotNetInstallerWindow.
• MainWindow.xaml & MainWindow.xaml.cs: Added OpenNETInstaller button and its click event handler.
• DotNetInstallerWindow.xaml & DotNetInstallerWindow.xaml.cs: Created new window and logic for .NET 8 installation process.