file_sys: Add factory class for RomFS file system.

and make the mode parameter a reference since it is a BitField union

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

This allows Fire Emblem to boot again.

Format information is currently only implemented for the ExtSaveData, SharedExtSaveData and SaveData archives, the information is stored in a file alongside the root folder of the archive.

This doesn't return by reference so const isn't really necessary

Fixed a few warnings and cleaned up the code

They will be stored in /extsavedata/SDMC and /extsavedata/NAND respectively.
Also redirect some APT_A functions to their APT_U equivalents.
Implemented the gamecoin.dat file in SharedExtSaveData in the PTM module.
Implemented formatting the savegame.
Retake a previous savegame if it exists instead of reporting them as not formatted every time a game is loaded.

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.

- Refactor FS::Archive internals to make Archive creation and lifetime
  management clearer.
- Remove the "Archive as a File" hack.
- Implement 64-bit Archive handles.