Populate gitaly and gitlab-shell image versions using appVersion
Similar to how we did the regular gitlab version: https://gitlab.com/charts/gitlab/issues/479
Except this time there won't be a global to set them.
But we should have them default to their chart appVersion, so that we can change their version with a script, the same way. (https://gitlab.com/charts/gitlab/issues/481 will need to update them)