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
You should be able to initialize this via `FileSys::Mode mode = {};`, assuming `hex` is its first data member. An explicit `mode.hex = 0` initialization is then not necessary.