[TIMOB-28302] macOS: Add checkbox style to Ti.UI.Switch

*Summary:* Apple's UISwitch support a checkbox style for Mac Catalyst apps as of Big Sur. https://developer.apple.com/documentation/uikit/uiswitchstyle *To-Do:* Titanium's Ti.UI.Switch currently supports an Android-only [style](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.Switch-property-style) property which can be assigned the following constants... * [Ti.UI.Android.SWITCH_STYLE_CHECKBOX](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.Android-property-SWITCH_STYLE_CHECKBOX) * [Ti.UI.Android.SWITCH_STYLE_SWITCH](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.Android-property-SWITCH_STYLE_SWITCH) * [Ti.UI.Android.SWITCH_STYLE_TOGGLEBUTTON](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.UI.Android-property-SWITCH_STYLE_TOGGLEBUTTON) We should move those constants to the Ti.UI module and add support for iOS builds. The TOGGLEBUTTON constant is Android-only and iOS should default to the SWITCH style instead. *Note:* iOS (ie: iPhone/iPad) does not support the checkbox style. This is only support by macOS apps. So, iOS app should use the switch style when assigned a checkbox style.