StdExtLib

This provides functionality that should be in the edk2 StdLib, but isn't, and that isn't large enough to be a library on its own. This also overrides some broken behavior in StdLib, so be sure to include Library/StdExtLib.h last.

There also a few overrides for StdLib that fix broken StdLib behavior or add features. These are effectively to be treated as part of StdExtLib.

What	Replaces	Notes
StdLibUefi	DevUefi	README.md
StdLibDevConsole	DevConsole	README.md
StdLibInteractiveIO	LibIIO	README.md

I ought to upstream at least some of these fixes. Without these fixes, the NetBSD tools in this collection will work even worse than they do now ;-).