"Undo" button in Edit mode

[tchapeaux]

When editing a barillet, it's easy to do some mistakes ("oops I deleted a theme card ☹️")

We should have a modification history and be able to undo/redo the changes. Maybe map it to CTR/CMD+Z as well?

We already have kind of the basis for it because we have a reducer function:

improv-barillet-editor/src/pages/home.jsx

Line 8 in e096f5a

function barilletReducer(state, action) {

So we would need to:

• Store each action send to the reducer in a stack
• Add a prevState attribute to the payload for destructive actions (e.g. for update: it would contain the previous value)
• Write a "reverseReducer" that does the undo action
• When clicking on "Undo", pop the last action from the stack and run it through reverseReducer
• Maybe "Undo" should be an action as well? 🤔 This might need some thoughts