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/playwright/tests/editor.spec.ts

@@ -0,0 +1,28 @@
+import test, { expect } from '@playwright/test'
+import { createTypebots, parseDefaultBlockWithStep } from '../services/database'
+import { defaultTextInputOptions, InputStepType } from 'models'
+import { generate } from 'short-uuid'
+
+test.describe('Editor', () => {
+  test('Undo / Redo buttons should work', async ({ page }) => {
+    const typebotId = generate()
+    await createTypebots([
+      {
+        id: typebotId,
+        ...parseDefaultBlockWithStep({
+          type: InputStepType.TEXT,
+          options: defaultTextInputOptions,
+        }),
+      },
+    ])
+
+    await page.goto(`/typebots/${typebotId}/edit`)
+    await page.click('text=Block #1', { button: 'right' })
+    await page.click('text=Delete')
+    await expect(page.locator('text=Block #1')).toBeHidden()
+    await page.click('button[aria-label="Undo"]')
+    await expect(page.locator('text=Block #1')).toBeVisible()
+    await page.click('button[aria-label="Redo"]')
+    await expect(page.locator('text=Block #1')).toBeHidden()
+  })
+})