feat: tlsping and tcpping using step-by-step (#815)

## Checklist

- [x] I have read the [contribution guidelines](https://github.com/ooni/probe-cli/blob/master/CONTRIBUTING.md)
- [x] reference issue for this pull request: https://github.com/ooni/probe/issues/2158
- [x] if you changed anything related how experiments work and you need to reflect these changes in the ooni/spec repository, please link to the related ooni/spec pull request: https://github.com/ooni/spec/pull/250

## Description

This diff refactors the codebase to reimplement tlsping and tcpping
to use the step-by-step measurements style.

See docs/design/dd-003-step-by-step.md for more information on the
step-by-step measurement style.

internal/engine/experiment/tcpping/tcpping_test.go

@@ -40,14 +40,16 @@ func TestMeasurer_run(t *testing.T) {
 		if m.ExperimentName() != "tcpping" {
 			t.Fatal("invalid experiment name")
 		}
-		if m.ExperimentVersion() != "0.1.0" {
+		if m.ExperimentVersion() != "0.2.0" {
 			t.Fatal("invalid experiment version")
 		}
 		ctx := context.Background()
 		meas := &model.Measurement{
 			Input: model.MeasurementTarget(input),
 		}
-		sess := &mockable.Session{}
+		sess := &mockable.Session{
+			MockableLogger: model.DiscardLogger,
+		}
 		callbacks := model.NewPrinterCallbacks(model.DiscardLogger)
 		err := m.Run(ctx, sess, meas, callbacks)
 		return meas, m, err