status/keyboard: Add menu items for IBus Anthy's InputMode, TypingMode

IBus has a properties API which are basically generic knobs into the
engine which are serialized and presented in a way that allows us to
easily build actionable UI elements with them.

Instead of implementing the whole generic system and accepting
everything coming out of the engines, for now, this patch just adds
support for a couple of important IBus Anthy properties.

https://bugzilla.gnome.org/show_bug.cgi?id=682314