feat(subp): Measure subprocess command time

[holmanb]

feat(subp): Measure subprocess command time

@smoser's idea

[holmanb]

Didn't implement this in the same log that subp currently emits since it is useful to see that log before the command is run, for debugging in case cloud-init crashes or hangs.

[github-actions]

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[TheRealFalcon]

This results in a ton of logs like this:

2023-12-01 03:32:20,754 - subp.py[DEBUG]: command ['hostname', 'me'] took 0.0s to run

and also adds a fair amount of extra logs.

I think we should either change %.3s to %.5s, or only log if the time elapsed is >= .1

[holmanb]

This results in a ton of logs like this:

Hmm, that serves no one.

only log if the time elapsed is >= .1

I prefer this way to avoid the extra logs.

[holmanb]

Rebased to resolve conflict with main.