feat(config)!: In config devices can now also be a (table of) function(s)

This function receives the mqtt client as an argument. In the future
this will be the only way to create devices that require the mqtt client.

definitions/config.lua

@@ -9,6 +9,9 @@ local FulfillmentConfig
 
 ---@class Config
 ---@field fulfillment FulfillmentConfig
----@field devices DeviceInterface[]?
+---@field devices Devices?
+---@field mqtt AsyncClient
 ---@field schedule table<string, fun() | fun()[]>?
 local Config
+
+---@alias Devices (DeviceInterface | fun(client: AsyncClient): Devices)[]