feat(NcAppSettingsDialog): adjust design for new form elements, add section descriptions and optional switch to legacy design

[ShGKme]

☑️ Resolves

• Fix [Meta] Forms design improvement #7124
• Added description for the NcAppSettingsSection
• Adjusted to the new design
  • To be used with NcFormGroup and NcFormBox components
• Added legacy prop to revert breaking parts of the new design
• ⚠️ Documentation improvement is in progress
  • Please do not review the documentation update
  • PR will be merged as it is, and the documentation will be adjusted later

🖼️ Screenshots

With legacy design

🏚️ Before	🏡 After

With the new design

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 51.60%. Comparing base (e3aa13c) to head (0f78429).
⚠️ Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7797      +/-   ##
==========================================
+ Coverage   51.57%   51.60%   +0.03%     
==========================================
  Files          96       96              
  Lines        3143     3145       +2     
  Branches      864      863       -1     
==========================================
+ Hits         1621     1623       +2     
  Misses       1274     1274              
  Partials      248      248              

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[AndyScherzinger]

Nice improvements / visual polishing 🎉

[susnux]

PR will be merged as it is, and the documentation will be adjusted later

[susnux]

/backport to stable8

[ShGKme]

PR will be merged as it is, and the documentation will be adjusted later

?

[ShGKme]

/backport to stable8