Removing a few more Result<bool> .

[dessalines]

Result<false> is confusing, when really we only want to a pass or fail check on a lot of these.

I've removed several of these a while back, but found a clean way to convert more of them.

[dessalines]

K this is ready to be looked at again. Some of the pass/fail checks needed to change their queries to select(not(exists from select(exists, to prevent a missing case from throwing an error.

IE a person block check should only throw an error if a row is found, not missing.

[Nutomic]

Waiting for @dullbananas to have another look, after that we can merge.

[dessalines]

There would be failing tests if my logic above wasn't right. I'll merge after this passes and we can correct later if necessary.