Add 'Presenter Mode' option for pointer

### Problem

When screen sharing or otherwise presenting one's screen, it can be hard to follow the mouse pointer. Simply making the cursor bigger could be a bit unwieldy to some, and the 'Find cursor' animation goes away too quickly to be used as a presentation pointer.

### Proposal

Provide an option to enable a 'Presentation Pointer' mode, where the pointer is highlighted constantly with either the 'Find cursor' highlight or some other form of highlight like a colored ring.

### Prior Art (Optional)