Use click and drag to draw the desired view port instead of using keyboard

[trassshhub]

Is your feature request related to a problem? Please describe.
Using keyboard to move and zoom the view port before tracking is less convenient than a simple click and drag.

Describe the solution you'd like
As we are already using click and drag to draw the tracking area, why not use the same mechanism to crop the desired view port?

Additional context
This should be straight forward for 2D videos, but 3D video might need some conversion.

[michael-mueller-git]

I've been working a little on your suggested improvement. The main problem is the implementation for VR, as you mentioned above, because i need to calculate the projection coordinates.
With the 2D Video menu, the possibility of adjusting the rotation of the image would be omitted with a normal 2 point mouse interface.