replace direct use of logrus?

[mmlb]

Opening this up here to have a single place for discussion regarding this. I've opened #138 and #139 with two implementations. #138 keeps logrus around (for now) and #139 just switches over to stdlib's log/slog library. @joelrebel @splaspood @turegano-equinix thoughts?

[mmlb]

I think I like go-logr/logr's api over log/slog but there's something to be said for being in the stdlib for log/slog. Both apis are pretty similar but I like that logr is explicitly Error and Info levels only and has V() to control which messages actually make it through. I also like that logr has an Error method that takes in an error.

slog has explicit methods for the different levels which is helpful if we use it (we do but only in a couple of files so not that big of a deal imo) but is in the stdlib which is a big +. I don't like that it doesn't have an Error method that requires an error argument though, we definitely use that a bunch. I don't really like the api for tweaking a slog.Logger though it only happens in main and examples.