Store Console credentials in secure storage during installation

[graikhel-intel]

Description

This story follows the implementation of secure credential storage in Console device-management-toolkit/console#1067

Once Console supports retrieving credentials from a secure storage mechanism, the default installer should be updated to use this capability during installation.

Instead of writing the initial username and password to config/config.yml, the installer should store these credentials in the supported secure storage mechanism and configure Console to retrieve them at runtime.

The installer should continue to provide a simple first-time setup experience while ensuring sensitive credentials are not persisted in plaintext configuration files.

Prerequisite

This story depends on the completion of the Console secure credential storage implementation: device-management-toolkit/console#1067

Scope

1. Update the installer to store the initial Console username and password in the supported secure storage mechanism.
2. Ensure credentials are not written to config/config.yml.
3. Configure Console to retrieve credentials from secure storage after installation.
4. Ensure install, upgrade, and uninstall workflows continue to function correctly.
5. Update installer documentation to reflect the new credential workflow.

Acceptance Criteria

• The installer stores the initial Console credentials in the supported secure storage mechanism.
• Username and password are not stored in plaintext in config/config.yml.
• Console successfully retrieves credentials from secure storage after installation.
• Install, upgrade, and uninstall scenarios are validated.
• Installer documentation is updated.
• Standard DoD