This enforced the idea that all generics must be specified for the type
when using the device macro. It will also come into play later when the
Typed macro gets introduced, as the name will be used when generating
definitions.
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.
This can be very useful if you want to convert a data struct to a lua
table without having to write the boilerplane (however small it may
be).
It also adds the macro on several state structs so they can be
converted to lua in the upcoming ActionCallback refactor.
