Add Wazuh v4.8.0 release notes

[s-ocando]

Description

This PR introduces the release notes document for Wazuh v4.8.0. Currently, there are no changes in the development change logs; we will include the changes as the change logs are updated.

Related issue: #6520

Checks

Docs building

• Compiles without warnings.

Code formatting and web optimization

• Uses three spaces indentation.
• Adds or updates meta descriptions accordingly.
• Updates the redirects.js script if necessary (check this guide).

Writing style

• Uses present tense, active voice, and semi-formal registry.
• Uses short, simple sentences.
• Uses bold for user interface elements, italics for key terms or emphasis, and code font for Bash commands, file names, REST paths, and code.