Reorganize documentation: split tables/trees and add templating guides

[oblomov-dev]

Summary

This PR reorganizes the development documentation to improve clarity and discoverability by splitting content into more focused guides and adding new documentation for XML templating and nested views.

Key Changes

• Split Tables and Trees documentation: Moved tree-specific content from docs/development/model/tables.md into a new dedicated docs/development/model/trees.md file, keeping tables documentation focused on tabular data
• Added XML Templating guide (docs/development/specific/xml_templating.md): New comprehensive guide covering dynamic view construction, conditional rendering, repeating controls, and composing fragments
• Added Nested Views guide (docs/development/view/nested.md): New guide documenting two approaches to building nested views—composing with helper methods and using sub-apps—plus guidance on when to use view_display for navigation
• Updated navigation structure: Modified docs/.vitepress/config.mjs to reflect the new documentation organization:
  • Renamed "Table, Tree" link to "Tables"
  • Added separate "Trees" link
  • Added "XML Templating" and "Nested Views" to the sidebar navigation
  • Removed OData link from model section (appears to be moved or deprecated)

Implementation Details

• All new documentation follows the existing format with frontmatter outline configuration and consistent heading structure
• Examples use the established abap2UI5 patterns and reference demo apps for further learning
• Documentation emphasizes practical patterns: helper methods for composition, sub-apps for responsibility separation, and server-side template resolution

https://claude.ai/code/session_0188k14QNhv7aWeXMPQHmxZo