Instead of being a function it now expects a struct with the
PartialUserData trait implemented. This in part ensures the correct
function signature.
It also adds another optional function to PartialUserData that returns
definitions for the added methods.
Instead of one function that contains all the device types available in
`automation_devices` a global registry is used were each device can
register itself.
This time with a bit more though put into the design of the code, as a
result the macro should be a lot more robust.
This did result in the macro getting renamed from LuaDevice to Device as
this should be _the_ Device macro.
The attribute also got renamed from traits() to device(traits()) and the
syntax got overhauled to allow for a bit more expression.
ActionCallback now only has one generics argument that has to implement
IntoLuaMulti, this makes ActionCallback much more flexible as it no
longer always requires two arguments.
