UI, libobs: Add Japanese shortcut keys for Windows

Add Japanese shortcut keys, non-convert (無変換) and convert (変換) and
disable IME for OBSHotkeyEdit.

Closes jp9000/obs-studio#930

UI/hotkey-edit.hpp

@@ -53,6 +53,7 @@ public:
 		// enough with the default focus frame
 		setReadOnly(true);
 #endif
+		setAttribute(Qt::WA_InputMethodEnabled, false);
 		setAttribute(Qt::WA_MacShowFocusRect, true);
 		InitSignalHandler();
 		ResetKey();