Automatically disable sleep timer if config without ut enabled is loaded

[DTSyX]

Maybe not really a "feature", but if technically possible a nice to have.

Currently (v.4.0 and before), if the sleep timer is enabled and one loads a settings config that has the sleep timer disabled it isn't automatically disabled by loading that config. One has to manually disable the sleep timer.
On the other hand, if the sleep timer is disabled and a settings config is loaded the sleep timer get enabled.

So, to make this behavior more consistent and logical, I propose, if possible, to make loading a config that has sleep timer disabled automatically disable the sleep timer if it is enabled currently.