[Request] Port functions from defunct InstallerOpt mod

[oroboros]

InstallerOpt: https://repo.xposed.info/module/net.fypm.installeropt

This module has been abandoned for two years now, and lots of people are still asking for it: (https://forum.xda-developers.com/xposed/modules/xposed-installeropt-0-4-t3377008)

What it did:

• Show version information when installing an application, current and new version numbers
• Automatically closing the installer when installation was successful so you don't have to click "Done" or "Open"
• Auto hide install and uninstall
• Auto install and uninstall
• Backup any currently installed application
• Backup APK files during install
• Manage all backups including restore from backups
• Delete APK files after install
• Disable application Force Close dialog
• Disable application verification and signature checking
• Disable system apps
• Disable user applications
• Display package name in app info
• Downgrade apps
• Enable clear data and cache buttons
• Launch app from icon in app info
• Open playstore link from icon in app info
• Show version info on installation window and/or as toast