text: Title: deprecate `ploomber cloud`
  Body: all the commands that begin with `cloud_` will be deprecated soon: https://github.com/ploomber/ploomber/blob/b69a6de7fc513fe27aababdae3d62cf350e0e04c/src/ploomber_cli/cli.py#L438
  
  so we need to display a FutureWarning with the following message: `ploomber cloud will be deprecated and replaced with a new system. If you need help migrating, send us a message to: https://ploomber.io/community`
  
  we also need to add a note (like the one we have [here](https://docs.ploomber.io/en/latest/user-guide/cli.html)) to all sections under [cloud](https://docs.ploomber.io/en/latest/cloud/api-key.html) with the following message: `Ploomber Cloud will be deprecated and replaced with a new system. If you need help migrating, send us a message to: https://ploomber.io/community`