Moved most of the shared CFG code there, implemented a few CFG:I functions

That's the language id block, we're using LANGUAGE_EN for now. This block allows some games to boot further

It is now kept in memory as per 3dbrew, all updates happen on memory, then they can be saved using UpdateConfigNANDSavegame.

Seems to allow some games to boot further, thanks @Normmatt for sharing this information

Added a "config" file to the CFG process service (CFG:U), and added a few default blocks to it.

Implemented GetSystemModel and GetModelNintendo2DS

Tested with hwtests.

- Removed unused VBLANK sleep mode
- Added error log for bad context switch
- Renamed VerifyWait to CheckWaitType to be more clear

More specifically, this also fixes crashes by Citra trying to load a src2 register even if the current instruction does not use that.

Makes for cleaner and faster code.

This allows for proper emulation of the different CMP/LRP/MAD instructions.