* Add minimum OS version to Info.plist
Add minimum OS version key to info.plist using a MACOSX_MINIMUM_SYSTEM_VERSION var, which can be set in CMakeLists.txt
* Set minumum OS to macOS 11 in CMakeLists.txt
Set the MACOSX_MINIMUM_SYSTEM_VERSION to macOS 11 Big Sur, which I believe is the current minimum version
* Use deployment target value rather than string
Uses CMAKE_OSX_DEPLOYMENT_TARGET instead of a hardcoded string to set the minimum OS
* Use deployment target global variable in Info.plist.in
Using MACOSX_BUNDLE_MINIMUM_SYSTEM_VERSION does not work, as CMake leaves it blank
* Update Qt CMakeLists.txt
Don't set MACOSX_MINIMUM_SYSTEM_VERSION as CMake leaves this blank
