Use GitLab base image as Gitaly base

What does this MR do?

Use GitLab base image as Gitaly base
    
Use GitLab base image as base for Gitaly instead of the ruby
image, as Gitaly does not depend on ruby anymore.
    
Changelog: changed

Related issues

Closes #524 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
  • debian (with charts): https://gitlab.com/gitlab-org/build/CNG/-/pipelines/1039722010
  • ubi (with charts): https://gitlab.com/gitlab-org/build/CNG/-/pipelines/1039818541
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes

• Documentation created/updated

• Integration tests added to GitLab QA

• The impact any change in container size has should be evaluated:

  > docker inspect registry.gitlab.com/gitlab-org/build/cng/gitaly:master | jq '.[] | .Size'
  895430841
  > docker inspect registry.gitlab.com/gitlab-org/build/cng/gitaly:524-change-gitaly-base-image | jq '.[] | .Size'
  670167771
  > docker inspect registry.gitlab.com/gitlab-org/build/cng/gitaly:master-ubi8 | jq '.[] | .Size'
  832889268
  > docker inspect registry.gitlab.com/gitlab-org/build/cng/gitaly:524-change-gitaly-base-image-ubi8 | jq '.[] | .Size'
  712408551

  • debian: ~ 220MB less
  • ubi: ~ 120MB less

• New dependencies are managed with dependencies.io