Add variables support to action windows

[antotor]

Hello! If this possible - please add variables support.

[justingiffard]

While this is possible, it would mean changing that number input view into a text input and adding some safety to the actions. I'm thinking I can do this though by having a checkbox to swop out the number input for the text one so as to not lose the features that come from using a number field for a static number 🤔

my question though, where all would you like to see this? on all the actions with "delta" in?

[justingiffard]

I added for all fader and pan deltas, let me know if threes something else you want it added to