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file_sys: Add factory class for RomFS file system.

file_sys/ncch_container: add RomFS, ExeFS override to allow for backward compatibility with existing .romfs system archive dumps

The loaders now register each loaded ROM with the SelfNCCH factory, which keeps the data around for the duration of the emulation session.

When opening the SelfNCCH archive, the factory queries the current program's programid and uses that as a key to the map that contains the NCCHData structure (RomFS, Icon, Banner, etc).

3dsx files do not have a programid and will use a default of 0 for this value, thus, only 1 3dsx file with RomFS is loadable at the same time.

* loader/ncch: split NCCH parsing into its own file

* loader/ncch: add support for loading update NCCHs from the SD card

* loader/ncch: fix formatting

* file_sys/ncch_container: Return a value for OpenFile

* loader/ncch: cleanup, always instantiate overlay_ncch to base_ncch

* file_sys/ncch_container: better encryption checks, allow non-app NCCHs to load properly and for the existence of NCCH structures to be checked

* file_sys/ncch_container: pass filepath as a const reference

 - Deleted GetStatus() because it wasn't used anywhere outside of Core::System.
 - Fixed design flaw where the message bar status could be set despite the game being stopped.

- Made LoadKernelSystemMode return a pair consisting of a system mode and a result code (Could use review).
- Deleted ErrorOpenGL error code in favor of just having ErrorVideoCore.
- Made dialog messages more clear.
- Compared archive ID in fs_user.cpp to ArchiveIdCode::NCCH as opposed to hex magic.
- Cleaned up some other stuff.

Corrects a few issues with regards to Doxygen documentation, for example:

- Incorrect parameter referencing.
- Missing @param tags.
- Typos in @param tags.

and a few minor other issues.