Prism Launcher Portable 9.1

• Update to Prism Launcher 9.1
  • Nothing actually changed in 9.1; only the installer changed, which is why I hadn't updated it yet
• Prism Launcher Portable now works without Visual C++ Redistributable installed
  • Done by switching from MSVC to MinGW builds
  • As a result, the download is about ~12 MB larger and install is about ~56 MB larger
  • This doesn't include the ARM64 version, since Prism Launcher doesn't have a ARM64 MinGW build
• Fixed the "Sign in with Microsoft" button not working when Prism Launcher is installed on the system
  • Literally all I did was add portable.txt, which tells Prism Launcher to use an alternative method lol