scale and place camera input in frame

[ghost]

It would be neat if we could scale the camera input and place it somewhere in the frame. This would allow a 2 things.

1. when using the default background I show up huge behind the podium. Being able to scale my image there (making me smaller) would make me the appropriate size for the background

2. (arguably the more important point) being able to scale and place the camera input somewhere specific in the frame and using your hologram filter would allow people to use this as a background, which I think is probably the most important work anyone could do :)

I'm not super familiar with the code and I know a little python, so I could give this a shot with some pointers.

[vgsantoniazzi]

@fangfufu can you help us with scaling?

[fangfufu]

@vgsantoniazzi , sorry, this features is really low down on the list.