Lock down docker image versions

[franz-see]

@sczyh30 First of all, thanks for this blueprint! looks really good and is well documented

However, I think it would be better to lock down the versions of the docker images instead of relying on "latest". Otherwise, you might be in a constant bug fixing everytime a new docker image breaks your project.

For example, elasticsearch:latest, logstash:latest and kibana:latest can no longer be found. MySQL currently has Unable to load authentication plugin 'caching_sha2_password'. Keycloak fails on first startup with Caused by: java.sql.SQLException: Access denied for user 'keycloak'@'172.27.0.2' (using password: YES).

Currently, I havent been able to run the project because Im still trying to address these docker issues.

[sczyh30]

Hi, thanks for your suggestion. I'll try to find the right versions of Docker images and fix this later.