Change the time while cooking

[MathiasSchjoedt-Bavngaard]

You must add the functionality to extend – or perhaps shorten – the cooking time when the oven is actually cooking.
A simple way to do that is letting a press on the time button during cooking add an amount of seconds to the remaining time, and the cooking period will then be prolonged for that amount. The display should of course show the new remaining cooking time.
If this function can make the time go to 0 (zero), then the oven should stop immediately.
You are free to define the user interface, etc. for this function, but it will probably demand changes in several modules. If you can make good design choices, e.g. considering the single responsibility principle, that is an extra plus and will probably make it easier to implement and test.
E.g. you are free to add an extra button that detracts from the time – so that there is an add time and a subtract time in steps you define.