Mini-guide: Staking onboarding

# Where to display?
On the court page
![image](https://github.com/kleros/kleros-v2/assets/22213980/3f1569d2-36f9-4a66-a9a7-2b10d64d041f)

# Details
https://www.figma.com/file/b7DEUKDeHlOl4ocDTMv7UIhZ/Kleros?type=design&node-id=13324%3A171442&mode=dev

![image](https://github.com/kleros/kleros-v2/assets/22213980/9bb80574-7027-4fc1-98f2-cb40e5b5c256)
