Quadlet override service name

[ygalblum]

Does this PR introduce a user-facing change?

Yes

Allow overriding the service name on all Quadlet unit types
Due to dependency enforcement, all referenced Quadlet files must exist even on dryrun 

[ygalblum]

@Luap99 this is the PR that completes the support for overriding the generated service name. In addition to the code changes, it required some adjustments to the tests in addition to some new tests

[rhatdan]

@ygalblum could you rebase and repush.

[ygalblum]

@rhatdan Done

[ygalblum]

@containers/podman-maintainers PTAL

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Luap99, rhatdan, ygalblum

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