Split off Use Cases into own page, added AI use cases, and reorg'd cases into thematic sections

[thomivy]

Summary of changes

1. Split off Use Cases into own page from the index/overview,
2. Added AI use cases
3. Reorg'd cases into thematic sections with theme headers.
4. remodeled the feature cards and network configuration information
5. Moved both to the top of homepage.
6. config is also moved up in sidebar.

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Code Checklist

• I have tested that prove my changes are working as intended
• I have added necessary documentation (if appropriate)

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