feat: port-filtering experiment (#891)

Part of https://github.com/ooni/probe/issues/2005

internal/registry/portfiltering.go

@@ -0,0 +1,23 @@
+package registry
+
+//
+// Registers the 'portfiltering' experiment
+//
+
+import (
+	"github.com/ooni/probe-cli/v3/internal/engine/experiment/portfiltering"
+	"github.com/ooni/probe-cli/v3/internal/model"
+)
+
+func init() {
+	AllExperiments["portfiltering"] = &Factory{
+		build: func(config any) model.ExperimentMeasurer {
+			return portfiltering.NewExperimentMeasurer(
+				config.(portfiltering.Config),
+			)
+		},
+		config:        portfiltering.Config{},
+		interruptible: false,
+		inputPolicy:   model.InputNone,
+	}
+}