CFG: Implemented the GetConfigInfoBlk2 function.

Added a "config" file to the CFG process service (CFG:U), and added a few default blocks to it.

Implemented GetSystemModel and GetModelNintendo2DS
This function is an implementation (backend) of the DeleteConfigNANDSavefile function in cfg:i, I see no clues in 3dbrew that say this should invalidate the memory buffer, and the name itself suggests that it doesn't.