Add job to test minimal redis version compatibility

Overview

Create GitLab QA GDK docker images with components that follow minimum requirement guidance:

• Redis
• PostgreSQL

These images can be later used in scheduled QA pipelines to validate environments with min requirements.

Context

There is no test coverage for customers who run minimum requirement guidance. There are unit tests with PG min versions, but for Redis specifically such approach won't work because unit tests run sidekiq workloads inline.

Lack of coverage for Redis specifically caused a bug which affected several customers:

Gitlab release 16.8 breaks compatibility with r... (gitlab-org/gitlab#439418 - closed) affected customers who used Redis 6.0 version (related to Azure Cache providing 6.0 version, please see gitlab-org/gitlab#439418 (comment 1752259827)). Redis version in Omnibus was bumped to 6.2 in 14.8 so the customers who were affected mostly are the ones using Azure Cache or customers who have their custom Redis cluster.

Example of previous issue for creating GDK images Add a scheduled pipeline that creates and verif... (gitlab-org/gitlab-development-kit#1680 - closed)