HLE/APT: Initial HLE support for applets.

Currently only the SWKBD is emulated, and there's currently no way to ask the user for input, so it always returns "Subv" as the text.

src/core/CMakeLists.txt

@@ -25,6 +25,8 @@ set(SRCS
             file_sys/ivfc_archive.cpp
             hle/config_mem.cpp
             hle/hle.cpp
+            hle/applets/applet.cpp
+            hle/applets/swkbd.cpp
             hle/kernel/address_arbiter.cpp
             hle/kernel/event.cpp
             hle/kernel/kernel.cpp
@@ -150,6 +152,8 @@ set(HEADERS
             hle/config_mem.h
             hle/function_wrappers.h
             hle/hle.h
+            hle/applets/applet.h
+            hle/applets/swkbd.h
             hle/kernel/address_arbiter.h
             hle/kernel/event.h
             hle/kernel/kernel.h