Bug in example(s): view-proj-matrices buffer not duplicated per frame in flight

[johannesugb]

The avk::buffer mViewProjBuffer; is only there once, but there should be as many of them as there are frames in flight. This applies to the orca_loader example, and possible also to other examples. => Fix it!

With the low complexity of the shaders and the rather low GPU-load in general for the example applications, it is not really noticeable that these buffers are not perfectly in-sync with the currently rendered frame. It should become visible with more GPU-load though (should actually be testable/observable in orca_loader when loading a bigger scene).

Update:
The problem becomes very apparent when rendering a very big mesh (like an infamous terrain mesh) in the model_loader example.

Definition of done:

• The avk::buffer mViewProjBuffer; has been duplicated in orca_loader and filled according to the current in-flight-index
• It has been double-checked if the other buffers are properly duplicated in the same way if required. (Material buffers do not need to be, for example).
• The model_loader example has been checked for the same issue
• The ray_tracing_basic_usage example has been checked for the same issue
• The ray_tracing_custom_intersection example has been checked for the same issue
• The ray_tracing_triangle_meshes example has been checked for the same issue
• The compute_image_processing example has been checked for the same issue
• The vertex_buffers example has been checked for the same issue
• The framebuffer example has been checked for the same issue
• The hello_world example has been checked for the same issue
• If further examples have been added, they have been checked as well