[TIMOB-24289] Remove unused / invalid demo-projects from titanium_mobile/demos

We still have the old KitchenSink project in titanium_mobile/demos that use Ti.Include'd to manage the app context. The only way those projects are used (and only KitchenSink, not the others), is to validate test-cases in Xcode. That's why I'd like to clean them up and only place our usual test-case trigger-code in there:

var win = Ti.UI.createWindow({
    backgroundColor: '#fff'
});

var btn = Ti.UI.createButton({
    title: 'Trigger'
});

btn.addEventListener('click', function() {
    Ti.API.info('Hello world!');
});

win.add(btn);
win.open();

It is no breaking change and does influence the packaged SDK, so I've chosen the issue type "Story" for now.