Core: Add a new File class, obtainable from an Archive, and a stub implementation.

src/core/CMakeLists.txt

@@ -23,6 +23,7 @@ set(SRCS
             arm/interpreter/armvirt.cpp
             arm/interpreter/thumbemu.cpp
             file_sys/archive_romfs.cpp
+            file_sys/file_romfs.cpp
             hle/kernel/address_arbiter.cpp
             hle/kernel/archive.cpp
             hle/kernel/event.cpp
@@ -77,6 +78,8 @@ set(HEADERS
             arm/arm_interface.h
             file_sys/archive.h
             file_sys/archive_romfs.h
+            file_sys/file.h
+            file_sys/file_romfs.h
             hle/kernel/address_arbiter.h
             hle/kernel/archive.h
             hle/kernel/event.h