Provide generic support for changing settings Apple Events

[owenpshaw]

It appears that on Mac we'll have to apply many/most settings by opening up the System Preferences panel and checking boxes using the Apple Events system. Provide a foundation for doing these kind of operations from Swift code.

[christopher-rtf]

This task was broken into three subtasks:

1. Provide a wrapper for reading/writing property list (plist) files
   ISSUE Provide generic support for capture/apply using Property Lists #13 - COMPLETE

2. Research the various ways to send Apple Events and implement a wrapper if necessary
   For MVP10 (mac1.0 milestone), we will use the ObjC-based ScriptingBridge from Swift using custom AE wrappers as necessary. If we find more advanced requirements for Apple Events that ScriptingBridge cannot handle, we should revisit (or re-open) this issue and create a more powerful AE library in Swift. [But at this time, there are no known requirements for such an advanced bridge]
   COMPLETE FOR MVP10

3. Create a UI automation wrapper for the macOS Accessibility UI framework (to check boxes, etc.) without needing to involve Apple Events at all
   ISSUE Create Swift wrapper for System Automation ("Accessibility") API #14 - COMPLETE

Unless and until we need to create a more advanced Apple Events bridge (to handle features or work around bugs in ScriptingBridge), I am moving this feature to the Backlog and untagging it from milestone "mac1.0".