Display Input Signals on Speakers / Display Panel

[Cipri]

tl;dr: Display the Input Signals in the Programmable Speaker and Display Panel in the sidebar

When you mouseover a Combinator, the Input Signals are displayed on the sidebar. This makes sense as the combinators 'purpose' is to do something with the input signals.

Programmable Speakers and Display Panels also have a single purpose, "Do something with the input signals". It would be helpful to have them also show the Input Signals to make it easier to debug issues with them without needing to loop them to a power pole or something else. Especially on Space Platforms, as those often don't have any power poles.