Experiment with caching a shallow clone of the gitlab project

What does this MR do?

Reopening of !46909 (closed).

The shallow clone caching is enabled if the $ENABLE_SHALLOW_REPO_CACHING variable exists.

The full clone caching is enabled by default unless the $DISABLE_FULL_REPO_CACHING variable exists.

After merge and after the next 2-hour scheduled pipeline:

• Update the $CI_PRE_CLONE_SCRIPT in script at https://gitlab.com/gitlab-org/gitlab/-/settings/ci_cd and replace https://storage.googleapis.com/gitlab-ci-git-repo-cache/project-278964/gitlab-master.tar.gz with https://storage.googleapis.com/gitlab-ci-git-repo-cache/project-278964/gitlab-master-shallow.tar.gz
• Update the $CI_PRE_CLONE_SCRIPT in script at https://gitlab.com/gitlab-org/security/gitlab/-/settings/ci_cd and replace https://storage.googleapis.com/gitlab-ci-git-repo-cache/project-278964/gitlab-master.tar.gz with https://storage.googleapis.com/gitlab-ci-git-repo-cache/project-278964/gitlab-master-shallow.tar.gz

Related to #276220 (closed).