[FEATURE] Combine the results in the video container if it's an animation

[rabits]

Is your feature request related to a problem? Please describe.

The animation should lead to get the result as required by user, in case of video is required - the compose images should be combined to the video container.

Actually it's a bug partially - because when the user requests output to //out/out.mp4 - there will be just the latest rendered result, so it produces a broken video file (that is actually exr file).

Describe the solution you'd like

There should be a task for Agent I suppose to collect the animation frames together when they are completed.