Error Handler, MD Shell: Console scrolling

[vladikcomper]

This PR implements basic console scrolling when pressing D-Pad. This should be extremely useful if screen content doesn't fit vertically (e.g. backtrace is too long).

TODO

• Add Console.SetXYScroll macro;
• Add Console.VSync macro (maybe squeeze it in here?);
• Code size optimizations if feasible;
• Scrolling in MD Shell and Console.Run;

[vladikcomper]

This feature won't make it to MD Debugger 2.6, I'm changing target to 2.7.

I have concerns including scrolling config into console config (as a simple output device, it should be dumber), need to think of a better approach. Auto-scrolling also only works with ErrorHandler_PagesController, which is far from ideal and it 4-directional scrolling feels a bit odd.