refactor(config)!: Move scheduler out of device_manager

Due to changes made in mlua the new scheduler is much simpler. It also
had no real business being part of the device manager, so it has now been
moved to be part of the returned config.

src/config.rs

@@ -37,6 +37,9 @@ pub struct Config {
     #[device_config(from_lua, default)]
     #[typed(default)]
     pub devices: Vec<Box<dyn Device>>,
+    #[device_config(from_lua, default)]
+    #[typed(default)]
+    pub schedule: HashMap<String, mlua::Function>,
 }
 
 impl From<FulfillmentConfig> for SocketAddr {