Expose redis cache configuration to helm charts
Context
As a follow-up to Enable the use of Redis to cache database repos... (#461 - closed), we should expose the redis cache settings to the Helm charts in https://gitlab.com/gitlab-org/charts/gitlab.
This work can be done in Parallel and the changes introduced in chore: add configuration settings for new redis... (!1079 - merged) can be tested using the charts implementation.