[ML][pipeline] implement Valve::{setOpen, isOpen}

[ML][pipeline] implement Valve::{setOpen, isOpen}

ACR: TWDAPI-274

[Verification] Tested in Chrome DevTools with the snippets below, works
fine.

var pipeline_def = "videotestsrc is-live=true ! videoconvert ! videoscale"
                   + " ! video/x-raw,format=RGBx,width=16,height=16,framerate=10/1"
                   + " ! tensor_converter ! valve name=valve1 ! fakesink";

var pipeline = tizen.ml.pipeline.createPipeline(pipeline_def,
                                      function(state) {console.log(state);});
// READY
// PAUSED

var v = pipeline.getValve('valve1')
// Valve {name: "valve1", _pipeline_id: 1}

v.isOpen
// true

pipeline.isOpen = false
v.isOpen
// true

v.setOpen(false)
v.isOpen
// false

Change-Id: Ibdeaba23082356b5143c2a1796bbd181b4d5d027
Signed-off-by: Pawel Wasowski <p.wasowski2@samsung.com>