Unify logging by using logrus for jetstream logs (#2976)

I guess tests for the logging is rather unusual so I omitted tests for
this change.

* [x] I have added Go unit tests or [Complement integration
tests](https://github.com/matrix-org/complement) for this PR _or_ I have
justified why this PR doesn't need tests
* [x] Pull request includes a [sign off below using a legally
identifiable
name](https://matrix-org.github.io/dendrite/development/contributing#sign-off)
_or_ I have already signed off privately

Signed-off-by: `David Schneider <dsbrng25b@gmail.com>`

---------

Signed-off-by: David Schneider <dsbrng25b@gmail.com>

setup/jetstream/log.go

@@ -0,0 +1,42 @@
+package jetstream
+
+import (
+	"github.com/nats-io/nats-server/v2/server"
+	"github.com/sirupsen/logrus"
+)
+
+var _ server.Logger = &LogAdapter{}
+
+type LogAdapter struct {
+	entry *logrus.Entry
+}
+
+func NewLogAdapter() *LogAdapter {
+	return &LogAdapter{
+		entry: logrus.StandardLogger().WithField("component", "jetstream"),
+	}
+}
+
+func (l *LogAdapter) Noticef(format string, v ...interface{}) {
+	l.entry.Infof(format, v...)
+}
+
+func (l *LogAdapter) Warnf(format string, v ...interface{}) {
+	l.entry.Warnf(format, v...)
+}
+
+func (l *LogAdapter) Fatalf(format string, v ...interface{}) {
+	l.entry.Fatalf(format, v...)
+}
+
+func (l *LogAdapter) Errorf(format string, v ...interface{}) {
+	l.entry.Errorf(format, v...)
+}
+
+func (l *LogAdapter) Debugf(format string, v ...interface{}) {
+	l.entry.Debugf(format, v...)
+}
+
+func (l *LogAdapter) Tracef(format string, v ...interface{}) {
+	l.entry.Tracef(format, v...)
+}