Improved error logging

[hugoShaka]

Depends on gravitational/trace#110

Demo code:

err := trace.Errorf("oh no, it's broken")
log.Info("hello", "error", trace.Wrap(err, "callsite info"))

JSON log output:

# without stacktrace
{"timestamp":"2024-11-28T18:00:06-05:00","level":"info","caller":"log/slog_handler_test.go:50","message":"hello","error":"callsite info: oh no, it's broken"}

# with stacktrace
{"timestamp":"2024-11-28T19:45:00-05:00","level":"info","caller":"log/slog_handler_test.go:50","message":"hello","error":"callsite info: oh no, it's broken","error_trace":["github.com/gravitational/teleport/lib/utils/log.TestHugo","testing.tRunner","runtime.goexit"]}

Text output

# without stacktrace
time:2024-11-28 19:53:19.250706 -0500 EST INFO  hello error:callsite info: oh no, it's broken log/slog_handler_test.go:50

# with stacktrace
time:2024-11-28 19:50:04.904607 -0500 EST INFO  hello error:callsite info: oh no, it's broken error_trace:[github.com/gravitational/teleport/lib/utils/log.TestHugo testing.tRunner runtime.goexit] log/slog_handler_test.go:50

I'm not satisfied with the text output but I don't think a text-specific ReplaceAttr would make sense. Sny string containing whitespace currently leads to confusing logs and we might want to fix this issue more generally.