osbase/logtree.LeveledLogger -> go/logging.Leveled

This factors out the common leveled logger interface out of the logtree.
We want to use the same interface outside of logtree/supervisor usage
within the resolver code, which will be exposed to clients.

Change-Id: I299e76d91e8cefddf8f36f1e58432418c4694df2
Reviewed-on: https://review.monogon.dev/c/monogon/+/3411
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/core/consensus/logparser.go b/metropolis/node/core/consensus/logparser.go
index b403423..f825431 100644
--- a/metropolis/node/core/consensus/logparser.go
+++ b/metropolis/node/core/consensus/logparser.go
@@ -8,6 +8,7 @@
 	"strings"
 	"time"
 
+	"source.monogon.dev/go/logging"
 	"source.monogon.dev/osbase/logbuffer"
 	"source.monogon.dev/osbase/logtree"
 	"source.monogon.dev/osbase/logtree/unraw"
@@ -80,13 +81,13 @@
 	// Convert zap level into logtree severity.
 	switch e.Level {
 	case "info":
-		out.Severity = logtree.INFO
+		out.Severity = logging.INFO
 	case "warn":
-		out.Severity = logtree.WARNING
+		out.Severity = logging.WARNING
 	case "error":
-		out.Severity = logtree.ERROR
+		out.Severity = logging.ERROR
 	case "fatal", "panic", "dpanic":
-		out.Severity = logtree.FATAL
+		out.Severity = logging.FATAL
 	}
 
 	// Sort extra keys alphabetically.