refactor: move scrubbingLogger to the scrubber pkg (#394)

* refactor: move scrubbingLogger to the scrubber pkg

We need it exported so we can use it in the new implementation.

Part of https://github.com/ooni/probe/issues/1687

* fix test

internal/engine/model/logger.go

@@ -12,7 +12,7 @@ type Logger interface {
 	// Info emits an informational message.
 	Info(msg string)
 
-	// Infof format and emits an informational message.
+	// Infof formats and emits an informational message.
 	Infof(format string, v ...interface{})
 
 	// Warn emits a warning message.