feat(config)!: Device creation function is now named entry

It now has to be called 'setup', this makes it possible to just
include the table as a whole in devices and it will automatically call
the correct function.

definitions/config.lua

@@ -9,12 +9,14 @@ local FulfillmentConfig
 
 ---@class Config
 ---@field fulfillment FulfillmentConfig
----@field devices Devices?
+---@field modules Modules?
 ---@field mqtt MqttConfig
 ---@field schedule table<string, fun() | fun()[]>?
 local Config
 
----@alias Devices (DeviceInterface | fun(client: AsyncClient): Devices)[]
+---@alias SetupFunction fun(mqtt_client: AsyncClient): SetupTable?
+---@alias SetupTable (DeviceInterface | { setup: SetupFunction? } | SetupTable)[]
+---@alias Modules SetupFunction | SetupTable
 
 ---@class MqttConfig
 ---@field host string