🚀 New Icon and 🐛 Bug fixes

Added

• msix package for packaging Windows app.
• New logo for the app, Flutter Installer.

Changed

• Upgrade all dependencies.
• theme_mode_handler is now replaced with theme_mode_builder.
• Data models and imports refactored.

Fixed

• file_selector plugin now works as expected, added platforms packages
• Cancel not working, #9
• UserChoice is saved in between summary and customize views, going back does not reset all settings. fixes #14

Removed

• Deprecated buttons.