Support gitaly transactions pipeline

What does this MR do and why?

Adds the ability to run a package-and-test pipeline with gitaly configuration to support transactions

Also updates the existing praefect jobs to explicitly disable transactions. This should mean that when in the future we switch to transactions being the default we will have preemptively covered the inverse.

See: Allow gitaly configuration to use transactions (gitlab-qa!1237 - merged) for relevant gitlab-qa changes

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