Web Announcement Banner

[FelyCZ]

Description

We need the ability to display a global announcement banner across the entire website to easily communicate important updates, deadlines, or alerts to all visitors.

Requirements

• Create a new model (e.g., AnnouncementBanner) in the Django backend to manage the banner's content.
• Implement an admin interface allowing editors to:
  • Enable or disable the banner globally.
  • Edit the text/Markdown content of the banner.
  • (Optional) Set an expiration date/time when the banner should automatically hide.
  • (Optional) Select a style/color indicating severity (e.g., info, warning, success).
• Update the base template (base.html) to inject and display the banner at the top of all pages when active.