Add Filebeat and Wazuh dashboard keystore guides

[dariommr]

Hello team! I would like to recommend adding in the Installation Guide (and why not in the User Manual too) the creation of Filebeat and Kibana keystores to avoid having the usernames and passwords in plain text. For Instance:

opensearch.username: kibanaserver
opensearch.password: kibanaserver

This documentation can help you: https://www.elastic.co/guide/en/kibana/7.10/secure-settings.html Setting a keystore in this way:

sudo -u wazuh-dashboard /usr/share/wazuh-dashboard/bin/opensearch-dashboards-keystore create
sudo -u wazuh-dashboard /usr/share/wazuh-dashboard/bin/opensearch-dashboards-keystore add <variable>

ie: sudo -u wazuh-dashboard /usr/share/wazuh-dashboard/bin/opensearch-dashboards-keystore add DASH_PASS The secret variables set in the keystore can be used in this way in the configuration file:

opensearch.username: {DASH_USER}
opensearch.password: {DASH_PASS}

The same thing for Filebeat: https://www.elastic.co/guide/en/beats/filebeat/7.10/keystore.html

I hope this information could be helpful.