Switch to C++14 to use std::make_unique
HLE: Move kernel/archive.* to service/fs/
HLE: Rename namespaces to match move & fix initialization order
Service.FS: Do archive registration using IdCode instead of name
Service.FS: Rename FileSys::Archive to ArchiveBackend
Service.FS: Rename FileSys::Directory to DirectoryBackend
Service.FS: Rename FileSys::File to FileBackend
FS.Archive: Clean up treatment of archives and their handles

- Refactor FS::Archive internals to make Archive creation and lifetime
  management clearer.
- Remove the "Archive as a File" hack.
- Implement 64-bit Archive handles.
Work around libstdc++'s lack of support for std::hash on enums