Add announcement bar in mkdocs

[RizwanMunawar]

@glenn-jocher

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Documentation enhanced with blog announcements and UI improvements.

📊 Key Changes

• Disabled the dismissible announcement banner feature in the MkDocs configuration.
• Added a new HTML override to prominently display a link to the Ultralytics blog celebrating the one-year anniversary of YOLOv8.

🎯 Purpose & Impact

• Purpose: To keep the documentation users informed about the latest news and achievements without allowing them to dismiss the announcement banner.
• Impact: Users will be consistently aware of important updates and milestones such as the YOLOv8 one-year anniversary, leading to increased engagement with the Ultralytics community and resources.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0e7221f) 77.04% compared to head (96b22c5) 77.04%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7482   +/-   ##
=======================================
  Coverage   77.04%   77.04%           
=======================================
  Files         117      117           
  Lines       14331    14331           
=======================================
  Hits        11042    11042           
  Misses       3289     3289           

Flag	Coverage Δ
Benchmarks	35.55% <ø> (ø)
GPU	39.59% <ø> (ø)
Tests	72.36% <ø> (ø)

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[glenn-jocher]

@RizwanMunawar oh wow, have you tried this? Does it work?

[glenn-jocher]

@RizwanMunawar merging into my actions branch to test there!

[RizwanMunawar]

@glenn-jocher yes it works 💪