How to delete MSYS2 Installer

This lightweight package performs an unattended installation of MSYS2 using official installer. It is intended as an alternative to msys2 and msys2.install packages which might be a better choice for some users.

Major differences when compared to [MSYS2](https://chocolatey.org/packages/msys2) package:
 - Installation is performed from official `.exe` binaries instead of `.tar.xz` archives
 - Unattended installation only without any additional customization or configuration (not even `pacman --noconfirm -Syuu`)

Major differences when compared to [msys2.install](https://chocolatey.org/packages/msys2.install) package:
 - `msys2.install` package is currently broken and not yet approved
 - Support for unattended uninstall
 - QtInstaller window is visible so that user can track progress and optionally answer MessageBox that is hard to automate (e.g. Corrupt_Installation_Error)