Adjustments toward Phlexifying CAFMaker

[knoepfel]

This PR is intended to illustrate the kinds of changes that would enable CAFMaker's functionality to be conducive for the Phlex framework.

The biggest changes:

• Functions that were filling data objects now directly return them (sometimes std::tuple<T, U>s)
• Some art functionalities that were being used in deeply embedded functions have been extracted to higher-level functions (e.g. analyze(art::Event const&)).
• Some modest removal of art::Ptr<T> usage

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✔️ CI build for LArSoft Succeeded on slf7 for c14:prof -- details available through the CI dashboard

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✔️ CI build for LArSoft Succeeded on slf7 for e26:prof -- details available through the CI dashboard

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✔️ CI build for DUNE Succeeded on slf7 for c14:prof -- details available through the CI dashboard

parent CI build details are available through the CI dashboard

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❌ CI build for DUNE Failed at phase build DUNE on slf7 for e26:prof -- details available through the CI dashboard

🚨 For more details about the failed phase, check the build DUNE phase logs

parent CI build details are available through the CI dashboard