refactor(editor): ♻️ Undo / Redo buttons + structure refacto

Yet another huge refacto... While implementing undo and redo features I understood that I updated the stored typebot too many times (i.e. on each key input) so I had to rethink it entirely. I also moved around some files.

apps/builder/components/shared/Graph/Nodes/StepNode/StepNodeOverlay.tsx

@@ -0,0 +1,26 @@
+import { StackProps, HStack } from '@chakra-ui/react'
+import { StartStep, Step } from 'models'
+import { StepIcon } from 'components/editor/StepsSideBar/StepIcon'
+import { StepNodeContent } from './StepNodeContent/StepNodeContent'
+
+export const StepNodeOverlay = ({
+  step,
+  ...props
+}: { step: Step | StartStep } & StackProps) => {
+  return (
+    <HStack
+      p="3"
+      borderWidth="1px"
+      rounded="lg"
+      bgColor="white"
+      cursor={'grab'}
+      w="264px"
+      pointerEvents="none"
+      shadow="lg"
+      {...props}
+    >
+      <StepIcon type={step.type} />
+      <StepNodeContent step={step} />
+    </HStack>
+  )
+}