Allow flexibility to define a target submodule and its branch
This allows testing submodule feature branches in builds and deploys by abstracting the branch names that need to be checked out, into gitlab CICD vars.
Gitlab will be upgraded from 17.7.7 to 17.11.7 Thursday evening (20260402). See the Gitlab 17.11.7 Release Notes for a list of what's new. Expect services to be down starting 5:45PM CT (1745).
This allows testing submodule feature branches in builds and deploys by abstracting the branch names that need to be checked out, into gitlab CICD vars.