Is your feature request related to a problem? Please describe.
OutcomePositive/Negative are big words for "yes" and "no". There have been various places/discussions requiring added logic to handle the fact that "yes" for one probe means it is safe, but for another probe it means it's dangerous (most recently, #3816 (comment)).

Describe the solution you'd like
Replace OutcomePositive/Negative (i.e. "yes"/"no") with "safe"/"unsafe": OutcomeSafe/Unsafe, OutcomeGood/Bad, etc.

I believe this will be more immediately legible: "ah, I don't even know what this probe is looking for, but apparently the project is safe from it!"

It may also simplify evaluation logic, since we don't need to special-case probes where Positive is a bad thing: OutcomeGood will always increase a project's score, OutcomeBad will always decrease it.

Describe alternatives you've considered
Probes could be renamed so that OutcomePositive always means it's safe. But this can lead to "negative" probe names (doesNotDoX), which doesn't follow the general coding principle that "variables" should be in the affirmative.