Improvements on kitchen-sink example (#7641)
### Description
- improved React imports by using `import React from "react"` instead of
`import * as React from "react"`
- moved content of `@repo/jest-presets` package one level up and out of
/jest directory for better accessibility. (in order to import the jest
presets like `@repo/jest-presets/node` instead of
`@repo/jest-presets/jest/node` )
- update the main `README.md` to have updated apps and packages
informations
### Testing Instructions
Running `npx create-turbo@latest -e kitchen-sink` and then both `pnpm
dev` and `pnpm test` should work fine as they do already.
