[CA PoC] Setup ClickHouse on CI

Why are we doing this work

To build our features using ClickHouse, we should be able to run the tests on CI. Since ClickHouse will be used only in a few test files/cases, we could setup a separate section in the CI YAML files which inherits from the unit tests, with one extra addition: we need a running ClickHouse instance.

Implementation plan

  1. Implement a new docker image for ClickHouse within https://gitlab.com/gitlab-org/gitlab-build-images
  2. Add a new config section, similar to use-pg13: use-clickhouse23
  3. Define a new RSpec group where we use the standard test dependencies (rails, PG) and use-clickhouse23. RSpec should only run test cases with the clickhouse tag.

Verification steps

Make sure the previously implemented (#414588 (closed)) test cases pass on GitLab CI.

Edited by Adam Hegyi