Added clarifications in the Docker multi-node deployment

[davidcr01]

Description

Related: #6551
The aim of this PR is to add some clarifications in the Wazuh Docker deployment, specifically when changing the passwords: https://documentation-dev.wazuh.com/v4.5.3-rc1/deployment-options/docker/wazuh-container.html#change-the-password-of-wazuh-users

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.