When using "Generate player's sequences" it should not remove the existing sequences

[ReneRebsdorf]

What problem is this solving

With #953 it would be great if we can generate several sequences in one take, and have them automatically merged to a single video (i.e. being able to generate all sequences in a single "session/video"

I intend to use this to generate videos of a players deaths from multiple POVs (the players and his enemies).

This might run into problems similar to #1084

Proposed solution

Generating videos use the overlapping video support

Describe alternatives you've considered

Generating separate videos and using ffmpeg cli to merge them, albeit this means all rounds are viewed from 1 POV before starting over from a different POV