Renaming TouchpadGestureMonitor to GestureRecognizer

And other changes are just consequence of that: renaming all its subclasses, field names etc

Bug: 369817369
Test: All tests are passing
Flag: com.android.systemui.shared.new_touchpad_gestures_tutorial
Change-Id: I48e278e43d83258b5f6e26062747d9fe0b9ca9b5