[CI] Add demo certificates to the packages

[AlexRuiz7]

Description

In order to improve the user experience deploying wazuh-indexer, we will add demo certificates to the packages, so the application can be started out of the box without further configuration.

This will also make our development and testing easier.

Implementation restrictions

• The certificates will be deployed to the expected path (see opensearch.yml).
• The expiration date of the certificates will be as far in time as possible (about 10 years from now).