* feat: Add banner schema and model
* feat: Add optional JwtAuth
To handle the conditional logic with and without authentication within the model.
* feat: Add an endpoint to retrieve a banner
* feat: Add implementation for client to use banner and access API
* feat: Display a banner on UI
* feat: Script for updating and deleting banners
* style: Update banner style
* fix: Adjust the height when the banner is displayed
* fix: failed specs
