[request] Allow to renumber cameras in ExportAnimatedCamera

[FlachyJoe]

When using an image sequence, the ExportAnimatedCamera node uses picture filenames to number cameras. It can cause issue due to high numbers.
E.g. a file "P1100331.jpg" results in a frame at index 1100331 in Blender. It loads but this high number is not reachable in the timeline (max is 1048574).

It could be great to have a input to set a sequence shift and/or a switchable auto-renumber from 0.