Add new helper, refactor utility functions into separate module

[holmanb]

Additional Context

This PR changes no functionally in cloud-init. It adds a small helper (4 LOC, excluding docstring). The intent for this helper was mentioned here.

• commit 1) -> factor out some lifecycle management code into a shared module - at 3.3k LOC and growing util.py should be split into smaller chunks
• commit 2) -> Add a helper function that will help us get Make exception handling explicit #5202 landed. This PR adds lots of warnings which adds downstream risk for stable releases. This will assist us in introducing warnings while reducing the risk to downstream releases.

Test Steps

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[TheRealFalcon]

Nice refactor! I left a few nits, and a "make sure this is fine" inline, but nothing blocking.

[a-dubs]

few small docstring only changes requested but looks good otherwise! nice refactor, sir holman.

[holmanb]

@TheRealFalcon @a-dubs Thanks for the reviews!

[a-dubs]

Anything for you, @holmanb