Update index.md for better clarity and relationship between packages

[ekzhu]

• Make the releationship between packages clear.
• Entice users by showing preview of builtin capabilities and API by using runnable code snippet.
• Prominently feature extension discovery and creation.
• Updated description and "Start here if ..." note to help user choose where to start.
• Bring back stock plot using single agent, which works quite well.

Need help with:

• Float the package badges to the top-right of each box.
• Center each "Get Started" button.

Follow ups:

• Add autogen-magentic-one PyPI package for convenient installation of m1 CLI tool and magentic one Python API. Add magentic-one PyPI package for convenient installation of m1 CLI tool and magentic one Python API. #4907
• Add top-level tab for Magentic One MagenticOne top-level tab section #4858

Updated look:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.20%. Comparing base (2ff543e) to head (b792210).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4896   +/-   ##
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  Coverage   68.20%   68.20%           
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  Files         158      158           
  Lines        9960     9960           
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  Hits         6793     6793           
  Misses       3167     3167           

Flag	Coverage Δ
unittests	68.20% <ø> (ø)

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[jackgerrits]

I really like the apps, framework, ecosystem distinction. I wonder if having some representation of that on the actual site might be good too. Looks great to me though!

[gagb]

This is lovely!

[samershi]

This looks fabulous!

Noting comments about the tagline:

• @victordibia suggested putting "framework" back since it tells the reader what this tool is all about.
• I also think we should add "building" back otherwise it's unclear what we mean by "for".

So, maybe something like "A framework for building AI agents and applications"?