v1.0.0: feat: Update app name to KeyVault and add new assets

- Changed app name from "Authenticator App" to "KeyVault" in Info.plist.
- Added new icon assets: keyvault-icon.png and keyvault-splash.png.
- Updated AppIcon configuration in Assets.xcassets to include new icon sizes.
- Modified LaunchScreen.storyboard to use a new background image.
- Added LaunchBackground imageset for launch screen background.
- Updated pubspec.yaml to reflect new app name and added configurations for launcher icons and native splash.
- Updated widget test to import the app from the new package name.