Add Observe Strategies and Object Version Handling Section to LwM2M Documentation

[nickAS21]

PR description

This PR introduces important updates to the LwM2M documentation:

🔄 New Features:

• Added support for multiple Observe behavior strategies in LwM2M device profiles:
  • Single — one Observe request per resource.
  • Composite All — all resources observed via a single Composite Observe.
  • Composite by Object — resources grouped by object and observed via separate Composite requests.

These options give users flexibility in balancing traffic efficiency and granularity.

📘 New Section:

• Handling of Object Versions in the LwM2M Model Structure
  A new section explaining how ThingsBoard handles object versions during profile configuration and request execution. This includes:
  • How versions are matched between device and profile.
  • What happens when versions mismatch.
  • Examples of correct request paths using versioned object IDs.

🛠 Other Improvements:

• Clarified that profile settings are applied during client Registration and on the next Update Registration, depending on the session state.
• ⚠️ Added a note that all changes in profile settings are applied only if the model object version matches, as described in the new section.
• Minor language and formatting enhancements for clarity.

These changes help ensure users correctly configure LwM2M profiles and avoid version-related integration issues.

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